Brian's Blog

T.S. Erika

2009-09-03T08:35:00.007-05:00

Well we did get "Erika" named obviously the other day. My thoughts then were that if this system were able to survive, it would be a potential threat to the Southeast / Florida, and I think that theme still applies. This discussion will be brief due to time constraints, but despite Erika's lack of organization, one cannot ignore how persistent the deep convective blob has been to the east of the seemingly erratic / elongated center of circulation. I cannot recall seeing such persistent convection in such a disorganized feature, which I think speaks volumes as far as how decent this storm could have been with just a little better environment. I think more attention needs to be focused on shear at levels other than the standard 200mb-850mb level when doing analysis. It is clear there has been shear, even though the following map shows a shear pattern that while not ideal, isn't the worst by any means either.

Now, from the same site, look at what you see when only looking at mid level shear.

The color scheme obviously is different, but regardless of what anyone tell you, this makes it clear that there has been detrimental shearing going on (duh... when LLC and MLC cannot co-locate, that is typically why), just more focused in the mid levels.

So what about the future? Well, I think this still has a tough road ahead, as to me the shear pattern doesn't look all that great ahead of it the next few days, but it's not so bad to prevent the storm from growing some if the LLC can reform under the persistent deep convection. If this does not occur, the storm may stay on a westward path and face possible death by Hispaniola. A reforming would allow a farther north path and a much better chance at survival, perhaps even substantial growth if it can reach the Bahamas in about 4 days, when shearing should be less. Model trends have come north versus yesterday overall, though I think the GFDL and HWRF are way too agreessive on intensity.

Bottom line, if we don't get the LLC under the deep convection, Erika is in trouble. If we do, it still has a fight for a few days, but could get going more if it survives the next 3 days and winds up in the Bahamas, in which case there would actually be a hurricane threat for Florida or somewhere a up the Southeast Coast. The next 24 hours should tell us a good deal more in order to make a better assessment.

With Danny Gone, Eyes Turn to Next System

2009-08-31T10:12:00.002-05:00

So Danny was essentially a non-event, which wasn't a surprise, but I had figured it would keep its "named" status longer than it did, even though it wasn't a purely tropical system. In any case, he's gone, so we're left with tracking the system east of the Lesser Antilles, which looks close to if not already at tropical depression / storm status at this time, so a classification could take place by NHC later today or tonight. The environment through tomorrow or maybe Wednesday could be good enough for some steady development, though it is close, as it will be on the eastern edge of a pretty hefty shear zone. After mid-week, the environment doesn't seem to be very favorable to me, as the upper low currently causing the shear probably doesn't move away faster than the storm is moving, and add to this the fact that by the weekend, there may be a piece somewhere in the southern U.S. or Southeast left behind in the wake of the current cool trough to also add some shear to the mix. It seems that some are of the opinion that if this system survives and gets toward the Bahamas this weekend, then it is off to the races intensity wise, and I'm not sure that is the case. Mind you, that does NOT mean it can't be a hurricane at all, but comparisons to storms like Andrew, or even 2004's Frances seem premature by a long shot, as the pattern to me does not look nearly as favorable, as both of those storms had better upper air ridges to the north, noted by the 588 height line at 500 mb extending way farther into the U.S. Point here is that on the edge of ridges, you have to watch these little "garbage" upper air features that can dance around, and that needs to be considered when trying to figure out future intensity as well as of course track. I have posted the European model shear map at day 6 as an example of this. Despite a decent upper ridge in western Atlantic, there is a little weakeness on the western side, and as you can see on the bottom left image, assuming we do have "Erika" in the Bahamas this weekend, the environment is not ideal. Now, you say, well the model could be dead wrong. Sure, it very well could, but most models generally agree on the position of the ridge, which means we have to watch for these subtle weaknesses given the strong trough departing the East.

So all of that said, first off I'm not sure if this thing will survive the trek into the Bahamas (I'm assuming that is the general direction it should go, as the ridge should keep it from escaping out to sea before getting that far), but if it does, the enviroment to me does not scream major hurricane, but at the same time, there is the risk of downplaying it too much, as a minimal hurricane still is a formidable foe if you have to deal with it, and this system will have a hard time "escaping" out to sea, so the odds favor either 1) getting torn apart by shear in the coming days, or 2) a move toward the U.S, probably Florida focused, so it does bear watching of course. My discussion here is more geared toward some of the rumblings I have heard about this possible being the next "big one". I think it has quite a fight on its hand to get to that status. In any case, it will be interesting to track, as the fact that it has been slow to get going has allowed it to be more of a potential player than I figured it may be from last week.

Danny Update... Next Feature Flares Up in Eastern Atlantic

2009-08-27T08:38:00.002-05:00

Danny still doesn't look the greatest, though to me this isn't a surprise, as I've always felt a minimal hurricane was the highest potential max intensity for this thing all along. The center of circulation still has not seen convection wrap around it, and it wouldn't be a shock to see it reform farther east where the convection is deeper, which would mean the risk for an official landfall is much less. Even with the track I had, which was near Hatteras to Cape Cod, this was not really gonna be a big deal where most people live in the I-95 corridor, as rain from interacting with the incoming cool front was really the biggest "threat". However, it does look like the track I had will need to be nudged a bit to the east, and at this point, any landfall is probably relegated to around Nantucket and that's about it. All in all, this will be a storm that got talked about quite a bit by some, but will go down as something that in the grand scheme of things is quite insignificant.

But fear not all you tropical enthusiasts, as the next system may be forming in the eastern Atlantic, as we do have a wave that has flared up nicely, and is in an evnvironment that right now isn't too bad, so in the next few days, we could have Erika on the map. My guess right now is that this will have a hard time ever being a threat to the U.S, given that we will likely have at least one weak upper low dancing underneath the Atlantic ridge, which will probbaly act to guid this storm north of the Lesser Antilles, and then it would probably get steered back out to sea given the strong upper trough headed into the eastern U.S. next week, which probably will split and send a piece tailing into the Southeast. But obviously we're talking a long way out here, and plenty of time to watch this one.

We Have Danny!

2009-08-26T09:12:00.002-05:00

The system discussed yesterday has just been updragded to Tropical Storm Danny, as it has finally developed an established low level circulation, and the shear pattern has improved quite a bit versus 24 hours ago. The center of circulation is not embedded underneath the deepest convection, which until that occurs will limit how fast this can ramp up, but it's a big improvement. As for the future of Danny, I don't have a lot different to add to what I stated yesterday. My guess is that the strongest this can get is a category 1 hurricane, and my best guess at track is still toward eastern North Carolina (I think the upper ridge holds this farther west than the GFS model and it's cousins, the NHC hurricane models and GFDL), affecting Hatteras the most, then moves northward along the East Coast, perhaps making another "landfall" (assuming it is still a tropical entity, which I think it should be, enough to keep classified as Danny... we'll see) in southern New England as the next upper trough is focused back in the Midwest this weekend.

While not a "major" system, it could make things interesting right along the coast, though into the big cities of the East, I still think heavy rain is really the only notable threat here. I guess the track I have laid out would put New York and Boston at a higher risk for more periods of tropical storm force wind gusts, but still there I tend to think rain is a bigger issue than wind (keep in mind I mean the metro areas, not right along the shores of Long Island or over to Cape Cod).

This also puts us actually a little ahead of schedule for the 4th named storm, which typically occurs around September 1st... interesting given the slow start to the season!

The Hiatus Is Over - Tropical Threat to East Coast?

2009-08-25T08:30:00.004-05:00

Obviously it has been a long while since I posted anything here, mostly due to welcoming my second son into the world at the end of June, and obviously being pretty occupied on the home front since then. And of course there have been the usual commitments to the real job as well. But I am going to try and get back in the mode of updating periodically here, as we are headed for the more exciting time of year for many weather enthusiasts, which is the run up to the winter season!

But for now, it is still summer (which FINALLY came to the eastern U.S. this month), and we are still in tropical mode as well, even now with a threat to the East Coast perhaps! All eyes are on "Invest 92", an area of disturbed weather north - northeast of the Lesser Antilles, which is heading to the west-northwest currently. As of now, conditions are not all that favorable for development, at least not very quickly, but should improve over the next day or two, and I do think we'll have Tropical Storm Danny out of this. Now, where does it go? Well if you believe the U.S. models, it will turn harmlessly back out to sea. But other models say not so fast, and with good reason in my opinion. The GFS model seems pretty quick to develop this, and perhaps a bit north of where the true low level center will eventually wind up. Because a more developed system can be tugged north by any weak upper features, the GFS, by virtue of being faster with development, sends Danny-to-be off into the westerlies much faster, and stays well offshore. But given that the shear is not that favorable right now, I'd lean toward a slower development curve, and a path farther west. A pretty potent trough will dive into the Midwest this weekend, and that should mean we have enough ridging downstream in the western Atlantic, which also leads me to believe a farther west path, closer to the other modeling. This says to me that "Danny" has a much greater shot to impact the East Coast than Bill ever did, though I don't think this system gets as strong. It could organize enough to reach hurricane status, but the incoming trough should start adding enough shear to make it a tropical storm up the coast, so not the best of weekends at the coast, but where most people live in the I-95 corridor, it is probably more a rainmaker. What else will need to be looked at is the potential for the storm to interact with the incoming front and enhance rainfall even more, perhaps leading to some flooding concerns.

So the bottom line is that we should see Danny out of this, and my best guess right now would be a storm moving close to or into eastern North Carolina this weekend, then northward up the coast, probably as a tropical storm, presenting heavy rain concerns up the eastern seaboard, with most of the significant wind issues right along the coast.

First Tropical Storm of Season?

2009-06-26T12:09:00.006-05:00

Well we are almost through the first month of hurricane season, and so far have not had much to discuss. This is not entirely unusual, as many Junes do in fact wind up quiet. But we have a system now in the western Caribbean Sea that I think has a shot at becoming our first named storm of the season. The first image below is the satellite picture of the Caribbean as I type this, and I have posted the link for this above the image, since the image itself shown here is not one which will update, so by the time you read this may be old!

In any case, it looked better earlier, but is not in an ideal environment right now to develop. It should continue to drift northwest, perhaps passing just east of the Yucatan Peninsula of Mexico this weekend. Wind shear will be gradually subsiding some as well, so it is possible that by Monday it is able to organize into Tropical Storm Ana.

Where would it go from there? Well, a fairly strong trough will dig into the eastern half of the nation, which probably has enough influence to turn whatever is in the Gulf toward Florida. This path would not be one that would allow any storm to strengthen much though, as wind shear is forecast to increase in the northern Gulf by Tuesday in response to the incoming eastern trough. See the second image below for the forecast shear, valid Tuesday evening (courtesy of the fine folks at MDA!). Values greater then 20 knots are certainly unfavorable. This means that, while possibly holding on to "named storm" status, this would be pretty much just a rainmaker for Florida, as it could not possibly intensify much with this pattern in place.

The other option is that the trough does not pick up whatever is there early next week, which would probably mean a path more toward south Texas or Mexico given the ridge that would be to its northwest. But the environment could be a little more favorable for development on this course. I'd rate this as less likely than option one discussed above though. At least we have something to watch!

Carribean Satellite:

http://www.ssd.noaa.gov/goes/east/carb/avn-l.jpg

Record Heat in Houston!

2009-06-25T10:19:00.003-05:00

While June has not been a hot month at all for many locations, the heat has certainly cranked down here in Houston. The last 2 days have climbed above 100, and should again today. In fact, yesterday's 104 degree high set the all-time June record here. Then we have this morning's low of 84, which also broke the June record for highest minimum, and tied the all-time mark for any month. The stat of the day: Our low down here this morning was hotter than the hottest high in New York City all month long! It's a neat stat, but should not be valid after tomorrow, as New York City should finally get above the 84 mark.

What was odd about the 104 here yesterday is that we were able to achieve that without a 500 mb ridge of at least 5940m in intensity. That is hard to pull off, but the fact that much of this area has seen no measurable rain for 31 days is helping that, as with no moisture in the ground, all of the sun's energy goes into heating the air rather than some of it getting used up in evaporating moisture.

Looks like, barring something strange, this will be a top 3 hottest and top 3 driest June on record here. Hopefully we won't follow the trend of the other 2 hottest Junes on record, being 1980 and 1998, and July of those years also went on to be hot (especially in 1980). Unfortunately for those of us down here though, it is hard to forecast anything other than "above normal" for Texas in July given the pattern we have in place.

Blocking is King

2009-06-16T13:35:00.002-05:00

The term "atmospheric blocking" is something often used exclusively in the winter season, as it is typically a more influential feature to look out for during the cold months. I, however, personally think it doesn't get enough play in the summer. Sure it isn't as strong of a signal, but can still have quite an influence. Don't believe me? Well, the Arctic Oscillation has been quite negative the entire month of June so far, indicating more high latitude blocking. So below, I have posted first the map of June's anomalies to date (image courtesy of the fine folks at MDA), and second, the map showing the typically pattern when blocking in prominent in June. I'll let you be the judge here, but it looks clear cut to me that it can play quite a role. Also, the astute one may notice a lot of years in the second composite come from years where we either were heading hard into el nino or already had one in progress. Coincidence? I tend to think not!

Some Bootleg June Stats

2009-06-12T10:14:00.003-05:00

Interesting how so far, this summer (yes I know I'm calling it summer, as it is in the meteorological sense beginning June 1) has started off on the cooler side in most areas, other than for me down here in Texas... Yuck! I stole an idea from the easteruswx.com weather board, and went back and looked at some stats on 90 degree days in June for a few of the big cities in the East to see when the last time there was a June without a 90 degree day. There was a thread on this board about the last time New York has had a June without hitting 90, and I went back and looked at Philly and Boston as well. The reason I chose these sites is that they have not had a 90 so far this month, and do not seem likely to for the next week or perhaps two, taking us into late June. So if this idea is right, the window of opportunity would be getting pretty small. In any case, the last time Boston failed to get 90 in June was back in 1998. For New York, it was 1996, and for Philly you have to go back to 1982! It has been awhile indeed. This, it is possible we could get all the way into July, having had the hottest weather of the last few months in the East occur in late April rather than May or June!

In some ways, the lack of heat isn't a big shock considering the developing el nino and the impacts that such an occurrence tends to have on the global pattern, but even in similar years, you usually get a brief spike or two somewhere, so we'll see if we get on before the month is done.

Racing Toward El Niño

2009-06-01T10:11:00.003-05:00

The last couple of months has certainly brought about a rapid warming of the tropical Pacific waters, terminating the two year la nina event (yes the nina was interrupted for a bit last summer, but quickly returned). Now the focus is on what looks to be an oncoming el nino as we haed through this warm season and into next fall / winter. Of course nothing is a lock in weather, but given how rapidly the warming has occurred, and the time of year, it seems the move toward el nino will be tough to fight off, and a high end weak to moderate event is possible. Looking just statistically, if we reach the critical +0.5 above normal threshold in nino region 3.4 by June or even July, a moderate nino is the most likely, and even strong nino becomes more likely than weak. So from a probability standpoint, moderate has highest odds, then strong, folowed by weak, and lastly neutral. Again, this is only looking at the stats, not subsurface, PDO, or anything else. The state of the PDO, while it will rise in the next few months, in my view should help fight off attempts for any "strong" event, though something like 1972 cannot be ruled out. Looking at the subsurface, we appear to at least as warm or warmer than any of the devloping moderate ninos at this stage of the year, at least the ones in which we have data for. Thus, a moderate nino would appear to be the most likely call right now.

This of course would mean a less active hurricane season in terms of numbers than we have seen in most of the last 10-15 years if correct, but where the storms go is still the important factor anyway. There is always too much made of the number of storms, though to be fair, it is tough to predict who will see the most impacts from landfalls in a seasonal forecast, regardless of what anyone will tell you.

Anyway, in looking at the Spring pattern, we see a lot of things are very typical of a year in which we are seeing a developing nino. I know some have felt the nina ruled the roost for much of Spring, or that we haven't seen a lot of true nino effects yet, but the following two maps to me say otherwise. The first map shows the upper air anomalies for this Spring (Mar-May, as far as I plotted last week), and the second one is a composite of all Springs when we were heading toward a nino from a nina or neutral state. I think a lot of the major anomaly centers match up well, but you can be the judge.

Late Spring Doldrums

2009-05-22T11:42:00.003-05:00

Haven't posted in awhile, partially due to some mostly uneventful weather recently, and also focusing more on research. There was actually some noteworthy items this week though. An "unexpected" surge of heat came into parts of the Plains and Upper Midwest this week, sending Minneapolis to 97 degrees on Tuesday, May 19th, marking the earliest on record that they have hit a temperature that high. There was a solid front to the north though. In fact, at 5pm that day, temperatures just in Minnesota ranged from 34 up in the northeast to 100 in the southwesern part of the state! Unreal contrast for any time of year but especially in mid to late May! Wednesday was impressive as well. Ashland, WI saw a morning low of 33, yet hit 90 that afternoon. Try dressing for that weather! Or you could have been in Sky Harbor, where the temperature moved from 46 to 86 in 20 minutes, topping out at 88, and then falling back to 45 just 40 minutes after that peak! I would have loved to be outside there during that event. The Lakes are still cool, so when the wind was off the lake, they were stuck in the 40s, but for 90 minutes or so, the wind turned SW and brought in the much, much warmer air that sat just inland... wild stuff, but can happen when you get shallow cold layers like this that quickly mix out.

The craziness in the Upper Midwest is gone, leaving things kinda blah again since the system in the Gulf is just a rainmaker (and was / still is a hefty one in parts of Florida!). Hard to believe the month of may is about over, and we're about to begin meteorological summer as well as the hurricane season! But will the developing el nino (or so it appears to be developing) squash any chance for noteworty extremes in both cases? It could. Most of the best-fit analogs are not hefty in the total number of named storms department, suggesting mostly numbers in the 9-12 storm range. That would not mean a dud of a season though, since it just takes one to make a season memorable. As for the summer, the consensus seems to be for a relatively benign (or near normal) summer for much of eastern U.S, perhaps even below normal in some places, with warmth favored in interior West. We do have to be cautious of the 2002 analog though, which is arguably the best match to what has actually been happening this Spring globally and overall in North America, and that turned out to be a fairly hot summer nationally, so this is not a slam dunk. It does appear the el nino is for real though, perhaps going moderate by fall / next winter.

Incoming!

2009-05-08T09:53:00.004-05:00

Haven't posted for awhile, as I figured I'd leave the hurricane talk near the top for a bit, but had to throw this in here today, as we're witnessing one of the more impressive thunderstorm complexes I have seen in quite some time rolling across Missouri and headed into northern Arkansas and western half of Tennessee and Kentucky. These "MCS"s (mesoscale convective systems) are common in the spring when you get impulses in the upper levels interacting with a very warm, moist (and thus unstable) air mass, but this one has been exceptionally strong, with gusts estimated as high as 100 mph when it passed through eastern Kansas this morning. Baseball size hail and a couple of tornadoes have occurred as well in Missouri. Just glancing at radar / satellite imagery, you'd think a hurricane was moving through the region! What is also fascinating is that some of the strongest winds have actually occurred behind the strongest line of thunderstorms, as high as 85 mph as much as 30 minutes after the worst of the thunderstorms has passed! Very wild and impressive stuff! I've seen plenty of damage reports coming in from the affected areas, so hopefully everyone stays safe who is in the path of this over the next few hours.

Here is an image from around 8:00 central time this morning. Wow!

Hurricane Season Just Over a Month Away!

2009-04-24T13:03:00.005-05:00

Hard for me to believe, but we're steamrolling toward the start of another hurricane season. June will be here before you know it, and speculation about what type of season we will see is of course in full swing. The consensus seems to be for a near to slightly above normal year in terms of the number of named storms, though expected by most to be one of the quieter seasons we have seen in recent years, which of course have tended to produce more storms, or at least have more swirls named. The two big reasons citied for this are 1) cooler water in the Atlantic, and 2) a possible shift toward an el niño pattern.

The cooler water in the Atlantic should not surprise anyone, as we have had two years of la nina (though it rested last summer) hammer away at it. For those not aware of this, la nina tends to, over time, spill over into the Atlantic and result in stronger trade winds which can cool the waters of the tropical Atlantic. I have posted an image below of years at this time which followed two years of la nina (using the MEI, which is always my measure of ENSO) to show the tendency toward this cooler tropical Atlantic.

Compare to actual SST anoms shown here:

http://weather.unisys.com/surface/sst_anom.html

Now, given that we do not appear to have entered the long term negative AMO state yet, and the fact that la nina is fading away (or arguably has faded away), the waters could easily recover some, so this is not the end-all factor to look at here. In fact I'd be surprised if they don't recover some in the next few months, but probably not nearly enough to compete with the warmth of the waters in many of our super-active years.

This leads us to the ENSO state. A lot of models are on board with a move toward el nino as we move through the next few months, and the SSTA link above shows some warmer waters starting to show up in the tropical Pacific already. But it isn't always the actual ENSO state that is important, but rather, which way the trend is going. For example, the shift out of a nina pattern can be led by the atmosphere itself, meaning some nino-like characteristics can be present before an actual nino is seen or declared. Thus, in some cases, a weakening nina can have similar effects as an actual nino. So, regardless of whether or not we go into an official nino by later in the hurricane season, these factors would seem to support less activity than what we have averaged this decade (even removing the massive 2005 season total). The farther we get on the nino side of the spectrum, the less activity I'd expect. I'm not sure we move far enough into a nino to get a year quite as quiet as 2006 though, as somewhere between warm-neutral and weak nino seems a better guess to me right now (MEI somewhere in the 0.2 to 0.6 range?). In addition, it is worth pointing out that all these guesses as far as number of namded storms is kinda pointless in a sense, as it only takes one big one to make the season memorable, and really, it is very tough to pinpoint where storms will go, as they depend on the pattern present at the time of formation, so no matter what, everyone needs to always stay prepared if you live near the coast. The consensus of 11-13 named storms from most outlets I have seen is pretty tough to argue with though.

What could allow for more activity? Well should the waters warm more solidly and the atmosphere jolt back toward la nina, then we could see more than the consensus calls for, so that is where to look in the next couple of months. Typically it is late spring / early summer when ENSO "decides" its course.

Vacation Done... Back to Weather

2009-04-23T09:56:00.002-05:00

The worst part about vacations is that they have to end. I think I found my new favorite city in Zurich, Switzerland. What a fabulous place, from the scenery, to the easy access to public transportation, and just an all around good place to relax. Rome was nice as well, and even though I'm not Catholic, being in the Vatican as the Pope delivered his Easter Sunday message was quite an awesome experience.

It helped that the weather was absolutely beautiful... very warm with sunshine every day we were there. In fact, temperatures were running a good 12-15 degrees above normals on most days. We expected to need a sweater and light jacket on some days based on normal temperatures for time of year, but that wasn't the case at all (and no I had not spent a ton of time trying to forecast what it would be like haha).

But now things are back to the normal routine. It looks anything but "normal" though in the eastern U.S. this weekend into early next week, with a very impressive (for late April) surge of warmth that will bring a chance for at least a couple of days of 85-90 from the Carolinas all the way up to perhaps Boston. The good news is that this time of year does not bring much in the way of humidity, so it won't be as bad as the same temperatures in say, June through August. Still, highs 15-20 above normal for the time of year is pretty warm, so for those of you living in these areas, enjoy your early taste of summer!

Vacation Time!

2009-04-09T09:34:00.002-05:00

Haven't posted in awhile, as I've been preparing for my vacation to Europe. I will depart later today and return next weekend. Fortunatley the weather where I am going looks mild, albeit cooler than I'm used to this time of year down here in Texas.

Last week's severe weather event (talked about last time I actually posted) went about as planned. It just was not the setup for a major outbreak. Maybe I'll do some case studies or something at some point in the future as far as some key things to look for, for those who aren't already aware.

We had some wild stats from the Plains the other day. Gage, OK had a morning low of 14 Tuesday, but rose to 82 in the afternoon! Try dressing appopriately for that kind of day!

Anyway, I don't see a major outbreak of severe weather on the horizon the next few days, but some smaller scale events are possible per SPC's discussions. We may have to wait for the end of the month or early May for a more favorable overall synoptic setup, assuming continued progression of current Madden-Julian wave. These waves will also help play a role in the state of ENSO in the coming months, which of course has big implications on summer and even next winter (yes I know many are already wondering about that!).

I'll be back to posting after my trip.

Severe Weather Update

2009-04-02T12:27:00.002-05:00

I don't have a lot to change from yesterday's thoughts as far as the overall gist of the current severe weather situation. This just isn't looking like a major outbreak of tornadoes to me, which is a good thing of course, but again, does NOT mean you let your guard down if you are in the risk areas. I have posted the current radar (as of this typing) below, and you can see a lot of storminess already out there. Moisture is sufficient as is shear, but the oreintation of the trough incoming is not prime for a huge tornado producer in my view (see yesterday's post), and you can already see the linear nature of the storms in Mississippi. We'll have to watch for any isolated storms ahead of this line, along with spin-ups in any bowed out sections or breaks in the line. Damaging straight-line winds will certainly be a threat with these storms. We also have a lot of activity in Florida, with some threat for tornadic cells, though I would think with the clustered nature, straight-line winds would be more of an issue as well. So all in all, the categorical risk on the SPC map below looks good now that they've cut back on the moderate risk some, though I still think the probabilities for tornadoes may be a bit high, with risk for damaging wind gusts perhaps not high enough in the moderate risk zone. It's been a neat storm to track, and hopefully no one will get a major hit here out of this.

Should be more threats to monitor in the South over the next week or two.

Radar, followed by SPC risk map:

Severe Threat for Tomorrow, 4/2/09

2009-04-01T09:34:00.004-05:00

Now that we are closer to tomorrow's threat, we can hone in a little more than I did the other day. First off, check the first map below which shows SPC's risk areas for tomorrow. We still have a lead shortwave which veers winds in its wake tomorrow, and keeps the low level jet a little on the weaker side, though probably not as weak as last week's system saw initially. Still though, despite the veered LLJ, the surface winds look to have a more southerly component, which would give a decent 0-1 km shear vector, which for a tornado outbreak is the most important shear layer. I agree with SPC's moderate risk, but despite robust moisture and more than sufficient instability progged, you can color me skeptical on this being a "major outbreak" of tornadoes. I will preface this comment though by saying that if you live in the risk area, be ready! This stuff can be tricky and you don't want to be caught downplaying an event that has any potential to turn out serious.

But I will look to the past some here. The second map below is the progged 500 mb map for tomorrow afternoon. Note the strong, but sharp, and already trying to tilt negatively, shortwave headig toward the South. My reason for some skepticism is that such a pattern looks conducive for storms to fire early, and with stronger forcing due to tilt of trough, we get many storms that can more easily cluster together rather than discrete storms which in a sheared environment can be more of a tornadic problem. If you look at historical data, many (but to be fair, not all) of the big outbreaks in the south occurred with a trough that had a larger base and / or was actually more of a positive tilt variety. Why? Well, since the South almost always has a lot more moisture to work with, positive tilt means forcing isn't as strong, but still strong enough for isolated / discrete storms to fire. The third map below is from 4/7/06, which was one such major outbreak, but I could provide other examples.

In any case, as mentioned, I agree a moderate risk is warranted. I don't see it being a high risk day, or at least verifying as one at this time, and think the tornado threat will be confined mostly to initial storms in western half of moderate risk area, and then become mostly a wind / hail threat rather quickly, with spin-up tornadoes mixed in the clusters still a possibility. We're still 24 hours away though, so small scale details can still change, so stay tuned! Maps referred to above follow:

Basketball > Weather... Maybe More Interest Thursday?

2009-03-30T11:55:00.003-05:00

Well, internet issues again didn't allow me to post Friday as I had planned, but it looks like in an overall sense, the Friday - Saturday severe weather event did not live up to what some models had been portraying, which of course is good news for those that were in the path of the storm. As such, the weekend wound up a good one to watch some hoops. My forecast for a UNC title still is alive at least, though I only got half of the Final Four correct this year.

Anyhow, with basketball on a break until the weekend, it is back to searching for threats in the current weather pattern. The next notable threat I see is on Thursday, and interestingly enough is in many of the same areas that were under the gun back on Friday. The pattern seems to want to repeat itself to some degree, with a series of lows coming out of the Rockies and into the Plains, then heading to the Mid-Atlantic, and that is what looks to occur Thursday and Friday of this week. I have two maps below. The first is the 500 mb forecast off the NAM valid Thursday afternoon. Yeah the NAM is not known for being stellar beyond like day 1, but other models generally agree on this setup. The second map shows the 2 meter dewpoints progged for the same time period, along with the lifted index. Obviously there should be no major concerns as far as lack of moisture is concerned. But once concern that may limit the potential here is similar to what happened back on Friday. Note the white circle I have placed on the 500 mb map. Right now, models show this lead impulse taking some of the "energy" away from the second system back in the southern Plains. I put "energy" in quotes because it's an over simplification, but the net result is that this lead system again weakens the 850 mb gradient, and we wind up having to wait until later in the evening to get the low level jet to crank again, and with it being tucked close to the parent trough coming out of the southern Plains, it would seem to imply that the tornado threat would be limited mostly to a 2-3 hour window, and storms may wind up clustering rather quickly after that. SPC has highlighted an area basically from New Orleans to Jackson, MS eastward into the Southeast in their day 4 assessment, though my guess is that will wind up needing to cover all of LA and MS. Greatest threat to me looks to be in LA, MS, and AL, and I could see this being a moderate risk day at the present time, but of course this far out will need to be refined as the event draws nearer. SPC also highlighted a risk this weekend in parts of OK and TX into the lower Mississippi valley, but this hinges on how much moisture can get back into the region in the wake of the Thursday storm, so will have to assess this one later on.

Maps referred to above:

Severe Weather Threat Today... In My Backyard!

2009-03-25T12:06:00.004-05:00

Occasionally I get to write about weather in my own area, and today is one of those days. It's a tricky situation (always is down here regarding severe weather chances), but there is a risk of severe storms in parts of Texas and over into Louisiana later today and tonight, and yes, a couple of tornadoes are possible. This morning's cold front pushed farther south than expected though, but is heading back north as I type, which means warmth and moisture is back on the increase in southeast TX. We already have a severe thunderstorm watch in central Texas, mostly for hail. What to watch for later is 1) How much does the low level flow increase? And 2) Does the cap erode in SE TX, allowing storms to root in the boundary layer? Models show the low level jet increasing to over 30 knots later this evening just to my east, which is sufficent to get severe storms. Along and to the west of the LLJ axis is where the best tornado threat should be, provided the cap weakens enough. I see SPC almost pulled the "moderate risk" trigger here, and I can see that, but I feel that, given concers about the cap, a high end slight risk is the way to go. Sunshine has poked out here though, so we'll see what happens late afternoon into early tonight, which is when "prime time" would be.

A more significant outbreak of severe weather is still possible Friday and Friday night in far eastern TX into AR, LA, and MS. I still find it hard to imagine such a strong upper level storm like the one that is coming out of the Rockies (which will be a hefty late season snow producer from eastern Colorado into KS, OK, and parts of MO) can clash with such a warm, moist air mass without some fireworks. My guess right now is that SPC will go moderate risk in tonight's day 2 outlook for this event. As mentioned yesterday, this threat carries into the Southeast Saturday, still with some tornado potential.

And now we have a few models that show another storm around the middle of next week which could be a severe weather producer in the same areas, along with another snow threat from eastern Colorado into Kansas and perhaps parts of Oklahoma. Lots to keep track of here the next few days, so stay tuned!

BTW, here is today's tornado risk map courtesy of SPC, which I have no major disagreements with.

More Severe Weather On the Way

2009-03-24T12:32:00.007-05:00

Yesterday went about as I expected... not a huge outbreak, but unfortuantely I did read that there were a few injuries. Here are yesterday's reports:

Looking ahead, there is no rest for the weary, as severe weather season seems ready to take off as we move through the next couple of weeks. Each of the next few days we have chances for severe weather, all the way to Saturday. I don't want to downplay the next couple of days (which could include strong to severe storms in my own backyard tomorrow into tomorrow night), but clearly the most glaring feature on the maps the next few days is Friday into Saturday. The current system moving into the Midwest is not able to push far enough south to really "clean out" the warm, moist air mass in place, which will allow the late week storm to have a lot of "juice" to work with. Here is the GFS valid Friday afternoon, which is one of the more ominous model depictions:

That's a pretty potent upper level system coming out of the central / southern Rockies, which by the way will be an impressive snowstorm from Denver out into parts of Kansas and perhaps up into Nebraska then the Upper Midwest for this time of year. The GFS also has a sufficient low level jet in place across the lower Mississippi Valley. Take note also of the vort max shown over the TN / KY region. That is a key also, as subsidence in the wake of this feature may allow sunshine to maximize destabilization from eastern Texas into AR / LA / MS ahead of the main upper low, though again, this model solution is probably the most ominous, but all models show what could be a dangerous storm in these areas (again maybe down toward me, though capping usually squashes the threat here for the most part... we'll see), though some other models do not depict much of a low level jet in place. While the GFS may be overdone, it's hard to see how such a system at 500 mb wouldn't generate enough of a LLJ for some severe weather (you don't need a 40+ knot LLJ anyway), especially with the warmth and moisture in place. Anyway, can't really get too specific yet other than this, but everyone from eastern Texas across the South will need to keep an eye on this, and the threat may extend into the Southeast Saturday.

Longer term, numerous models show a trough more or less anchored in the means near the Rockies, so we probably are not done with severe threats after this week, provided enough warm, moist air stays in place. We also may see a trough hanging around off the Northeast as well, but if you recall the image I posted a long time ago (I'll have to dig it up again) that showed the "optimal" tornado pattern, you often see this. The reason is that such a setup leads to higher pressure in the East, with a south to southeasterly return flow in the middle of the nation, and this keeps low level flow backed enough to maximize directional wind shear. Bottom line... We probably will have a lot to watch in the next week or two at least.

Update on Severe Threat Today... More on the Way?

2009-03-23T09:01:00.003-05:00

Couldn't update this weekend due to internet issues, but the threat today is still contigent upon the dynamics making up for a relative lack of moisture (50s dewpoints can be enough, but you'd like to see 60s for a bigger outbreak of severe weather). One thing that looks more favorable than when I posted back on Friday is that we should have more directional shear in the KS / OK area than what I was expecting when I posted on Friday. I have posted a map of the 0-3 km shear vectors, and what I want you to do is imagine a north to south oriented front from central SD down toward central OK. Notice the shear vectors in KS / OK are oriented more perpendicular to the front, which gives storms more of a chance to remain supercellular rather than lining out, as may be the case farther north where the shear vectors are more parallel to the front. This is something to keep in mind when making an analysis of severe weather. Having said all of this, I really don't have a big disagreement with SPC's outlook for today. While there are limiting factors, a moderate risk is okay, though I'd be okay with a high end slight risk as well, given the borderline nature of the event. I may need a post to deal with a potentially more significant event later this week (Friday into Saturday), as models starting to look a little more ominous in that time frame from the mid-lower Mississippi Valley into the South.

Maps below are the 0-3 km shear vectors valid this evening, and the SPC outlook for today.

Severe Weather Threat Early Next Week?

2009-03-20T10:41:00.008-05:00

Things have been fairly quiet on the severe weather front lately, especially when considering how active the last few years have been so early on in the season. It remains to be seen if we ramp up activity later on, but we do at least have a threat on the horizon for early next week. I have presented a few maps below which you may refer too. All models agree on a fairly potent upper low coming out of the Rockies Monday, as shown on the first map below, which is the GFS 500 mb height / vorticity plot valid Monday afternoon. Notice a strong trough also though over the Northeast, which I think will limit the amount of time a solid return flow of Gulf moisture will be into the Plains to at least some degree. A month later in the season and this may not be nearly as much of an issue, but it is still late March.

The second map is also a 500 mb plot, but has the winds at that level rather than vorticity. Notice peak winds in the jet core coming into the Plains are over 90 knots, which is solid and easily can support a severe threat.

The third map below is the low level jet at 850 mb, which exceeds 50 knots in its core, again, well over what you need to see to generate strong to severe storms. Given the low level jet's intersection with the 500 mb jet over central Kansas, this would be a favored area for severe weather, provided enough moisture and instability is in place, which may be the limiting factor. The final map shows that dewpoints are expected to be mostly in the 50s, as opposed to 60s, which would be a more favorable environment for storms. Also, this return flow looks rather dirty to me, meaning clouds and light precipitation may cover much of the warm sector, limiting how unstable the atmosphere gets, and indeed models show the highest instability will be limited to a narrow strip ahead of the front.

So my guess is that we will have a few severe storms from central Nebraska into Kansas, Oklahoma, and north Texas, with a few supercells possible despite limited moisture content. The area at greatest risk to me would appear to be central Kansas if I har to pick a spot, with perhaps a secondary area in southern Oklahoma / north Texas as core of 500 mb jet punches eastward in the evening Monday. An isolated tornado or two cannot be ruled out in my opinion as initial storms form Monday afternoon or early evening, but the flow has a strong southerly component at all levels, and the instability axis is pretty narrow, so my guess is storms will "line out", or aggregate together in a linear fashion quickly, making hail and gusty strightline winds a bigger threat as the event unfolds Monday afternoon / evening. There may be a threat for isolated severe storms Tuesday farther east toward the Mississippi Valley, but should be less of a threat than on Monday.

Biggest Piece of Evidence Yet of Global Warming

2009-03-17T12:33:00.006-05:00

This is perhaps the single most important proof that global warming indeed is occurring, but makes the case that perhaps we should let it continue a little longer first. :)

I received this in my email this morning. Nothing like a little light-heartedness on what is a rather dull weather day! Ooh but the GFS is ready to put the eastern U.S. back into the ice box toward next weekend (not this coming one) and beyond! Stay tuned!

Weather Doldrums

2009-03-16T14:17:00.002-05:00

Haven't been around to post for a bit, but am back to the regular routine for now. This is typically the time of the year when we have to start turning our attention toward severe weather / tornado outbreaks as winter fades away. Winter indeed is fading away, but for right now we're not seeing any notable severe weather chances on the horizon. In fact, the weather is downright boring for the most part (yes, for most people sunny and warm is not boring, but in the world of a meteorologist, there needs to be something a little more exciting).

We did get some exceptional cooling into Texas last Friday through yesterday. In fact, if you go back and look at historical records, a co-worker of mine found that for the 3 day period of March 13-15, each day from Friday to Sunday ranks in the top 5 coolest days in terms of how low the daytime high was (the highs these 3 days were 46, 48, and 54 respectively). So it was definitely an impressive event for down here.

Elsewhere, we're still locked into a la nina base state overall, and in fact, forecasts for this week are now warmer in much of the middle of the nation than what was in the forecasts back on Friday, which is no surprise since it is here where a la nina spring tends to focus its warmth. You often will get cooling opportunites closer to both coasts. The global angular momentum isn't as low as it has been though, but it remains to be seen if this is a sign of the end for this la nina state. Most long term modeling is actually favoring more of an el nino look down the road (later this year), so figuring this out will be key in figuring out what goes on this summer, and for you winter lovers, what type of winter we may see next year. But let's not get too far ahead of ourselves here.

I do still plan on typing up a quick review of this winter sometime soon, and will talk about how things turned out versus the consensus forecasts. We'll point out the good, the bad, and the ugly. Perhaps during this weather "downtime" I can also go into some of the global teleconnections and what they mean, if there is an interest there.

Texas Chill... Still Not Done With Winter?

2009-03-11T14:02:00.005-05:00

One of the more impressive features on the weather map is the strong front heading into Southeast Texas as I type this. I touched on this the other day, and showed one model which was predicting temperatures would stay in the 40s Saturday afternoon. This type of chill is becoming reality, and in fact it isn't out of the question that most of tomorrow, Friday, and Saturday is spent in the 40s. To many, this doesn't sound like a big deal, but down here, where normal highs are in the 70s, it is pretty wild, and may in fact break the daily records on Friday and Saturday for the coldest high temperature on that date. Oh and I haven't mentioned the cold rain to go with it. I'm hoping we can at least salvage a drier Saturday night into Sunday, but we'll see. Definitely looks mega-dreary tomorrow through at least Saturday afternoon down here, though to be fair, the rain is badly needed across Texas. Here is a current map (won't be current when many of you see this of course), which still shows some warm air in Houston, but not for long, as the chill cometh!

Next topic... Still unable to say the books are closed on winter. It remains a possibility that some wet snowflakes fly with that southern stream energy in the Lower Apps / Mid Atlantic (down into VA) Friday morning, though shouldn't amount to much with marginal temperatures. Only the mountains are fair game really for a small accumulation I would think, but something to watch. And then there is next week, as the European model wants to bring one final dumping into the East around the middle of next week, with a very amplified pattern, which I have shown below. Is this possible? Well, sure it has a chance, but the Euro model seems to be an outlier right now with this kind of amplification, so I wouldn't hold my breath on this, not that most people would do this anyway given it is the middle of March, but stranger things have happened! Really the same key would apply as has been the rule all winter... getting a slower / more amplified northern stream, and frankly, with AAM not jerking strongly in one direction or the other as of this writing, it is a tough call a week away. We got it to work out once... We'll see if luck can strike twice. Stay tuned!

Welcome to DST!

2009-03-09T13:34:00.006-05:00

"DST" being daylight saving time, which I loathe, as it means my workday is an hour longer (no the computer models do not run an hour earlier to compensate for the time change). But alas, I won't rant too much about that minor inconvenience here!

Although there isn't much in the way of extreme weather to talk about in the near term, with the exception of the possible blizzard in the northern Plains in the next couple of days, we do still have some things to watch for. First is the chance for isolated severe weather in the Midwest the next couple of days, but it doesn't look like a big event, so I won't talk much about that. I will turn more toward severe weather though as larger threats come down the road, so stay tuned for that. I showed in my last post the big temperature contrast from the warm side of this week's front to the cold side, and it does still look like quite a reversal later this week, starting in the Plains / Midwest and spreading east. I also said I was watching a southern stream feature in case it can produce any wintry mischief (or fun, depending on your perspective) this weekend, and this is still on the table. Sure, it is a long shot, but somewhere from the Apps of the Virginias into the Northeast could see something out of it given the cold in place, if the feature can come far enough north. Most recent GFS run says to at least keep an eye out.

Yes, the GFS 6.5 days from now is not the most reliable, but hey, I said it's a long shot, and it is (though not impossible), but at this point is all we have to really watch in the eastern U.S.

Turning to my own backyard, I'm torn on this weekend. I have outdoor plans for the first time in awhile, and wouldn't you know it, it looks rainy, which hardly ever happens down here anymore. To make matters worse, it looks quite chilly for this time of year too. Some of the cold air coming out of Canada gets down here later this week, and at the same time, the southern stream feature in the Southwest (same one to watch in the east toward the weekend) comes out, and moisture "overruns" the cooler air at the surface. Typically, a southwesterly flow bring in warmer air, but in this case clouds and rain effectively trap cooler air in the low levels. Below is the GFS model's idea for Saturday afternoon. Yes that is 40s shown for most of Texas even in the afternoon, with the chilly rain to go with it. Yuck. This model may be overdoing the cool air, but right now I tend to think much of Saturday is spent no warmer than low / mid 50s down here. Good news is we need the rain badly, though I'd like it to wait a couple of days longer.

Back in the Saddle

2009-03-08T11:12:00.007-05:00

Haven't been able to post for a couple of days due to my sick child, but thankfully that is better now so I'm getting back into the routine now where I can fully focus on weather (which is good since my job depends on it!). I'll try to get into some more interesting things late this week, like reviewing the winter, and of course looking ahead more.

This week is pretty interesting though in and of itself. There is a minor snow event for parts of New England tonight into tomorrow. We also have a lot of warm air from the Midwest (some severe weather today, which I haven't really had time to analyze) into the South that will battle (and lose out in many areas) to some very strong cold sitting to the north, which pushed south and east this week. Parts of Canada are looking at temperatures over 30 degrees below normal early this week! Below I have posted one model's prediction of temperatures by Tuesday evening, and you can see the battle underway.

That is 70s showing up in parts of the lower Midwest, and below zero up in parts of North Dakota! The Dakotas in fact will get quite a blizzard out of this. To most people, this isn't interesting since not that many people live there. Fine. But I will say that as this cold pushes east, a lot of folks especially from the Midwest to Northeast may be surprised by its intensity, especially given the warm start to the week in a lot of areas. This, by the way, is in response to the AAM spike I talked about a couple of posts back, which is temporarily taking us out of the la nina base state (yes I stole this whole "base state" talk from NOAA's Ed Berry, as I think it is a good way to describe things). Can we get a storm to arrive as the colder air is here for any late snow threats? Nothing definite is showing up on the horizon, but watch a southern stream wave next weekend that could pull some funny stuff from, say, Kansas to the Mid-Atlantic.

The nina base state I think should come back later in the month though, and models are starting to fall into line with this idea (maybe that should worry me given how bad they've been at times?). This nina state in Spring typically means warmer than normal from Central Rockies to western Midwest and down to Texas, though leaves a risk for coolings along both coasts. Going a little IMBY here (you weather board folks know what this means!), la nina base states in spring with a very dry Texas already in place do not please me when thinking about summer, but that is for another time.

Global Warming on Hold?

2009-03-05T11:15:00.003-06:00

http://dsc.discovery.com/news/2009/03/02/global-warming-pause.html

Please read the above link. Back when I started this blog, I posted about how global temperatures have stopped rising, and opined that this halt in warming (perhaps even with some global cooling) could persist for the next 10-20 years given some of the climate shifts and odd solar behavior we are seeing. Well, it seems that this has dumbfounded some climate "scientists". I put scientists in quotes because I cannot figure out how some of the junk they say is even worthy of being called science. Consider a portion of what is shown in the article concerning the halt in the warming in recent years.

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"This is nothing like anything we've seen since 1950," Kyle Swanson of the University of Wisconsin-Milwaukee said. "Cooling events since then had firm causes, like eruptions or large-magnitude La Ninas. This current cooling doesn't have one."

Instead, Swanson and colleague Anastasios Tsonis think a series of climate processes have aligned, conspiring to chill the climate. In 1997 and 1998, the tropical Pacific Ocean warmed rapidly in what Swanson called a "super El Nino event." It sent a shock wave through the oceans and atmosphere, jarring their circulation patterns into unison.
----------------------------------------------------

This Swanson guy is a climate scientist? So he mentions that large la ninas can lead to cooling, yet cannot find any explanation at all as far as what is going on. Hello! You might want to actually check out some actual data! Or we could just choose to ignore the fact that we are in the second year of a LA NINA, which was actually a pretty strong one last year. And the second paragraph above... the strong el nina jarred circulations into unison? That doesn't even make any sense, but since a supposed climate scientist cannot even tell we've been in a solid la nina, I guess nothing more should be expected.

At the end of the article, Swanson then states that this "halt" may go on for 30 years, but says "explosive" warming WILL resume thereafter! Gee, thanks. I'm supposed to believe that someone who apparantly cannot recognize a la nina, and admits to not having a clue what is going on right now somehow has what will happen 30 years and beyond all figured out. Forgive me for having no faith in this.

As I have said previously, the point is not that I doubt the role of human influence in global warming (some will read this and make that blind assumption). I think it probably is there. We just don't know if we account for 5%, 50%, 75%, or whatever. Until we have a better understanding of natural cycles (which this shows we obviously don't), there is no way to quantify our role in it.

Can We Close the Books on Winter?

2009-03-04T11:44:00.007-06:00

The snowstorm the other day, while satifying many of the snow lovers along the eastern seaboard and even into the South, has left many people wondering, can we squeeze out anything else this season? Is the pattern still favorable as it turned out to be for this previous event? Well, truthfully, if you live south of 40N latitude, yes it is getting pretty late, though not impossible, as some storms of the past have shown. Farther north stays in the game much later of course.

Anyway, to the present... We are about to get an impressive warm surge into the East this weekend to erase much of the snowpack built up the other day. We could see temperatures reach at least 75 in Washington D.C, and perhaps flirt with around 70 in New York City. Even back to Chicago and Detroit should see temperatures reach the 60s. Certainly this will turn most people's thoughts to Spring, but we do have another interesting situation atmospherically going on currently. Note the first map below. It is the tendency of the global angular momentum (AAM), and is currently off-the-charts positive. We have been in the tank negatively for awhile, and recall negative AAM is a nina-like state, while +AAM is more typical of a nino state. And yes even in a la nina or el nino you can get temporary AAM cycles that support an opposite pattern. This spike upward in tendency indicates we may do just that. This should lead to addition of westerly flow coming off eastern Asia, and push the upper ridge currently in the north-central Pacific closer to the West Coast. This would lead to chances for colder air intrusion again farther east. Indeed, the second map, showing the model prog for 10 days away shows this ridge west / trough east alignment, and for those of you who know your climo, you can see this is a more nino-is look than nina. Also there is a hint of blocking in the Atlantic too, which can sometimes occur at times as a result of AAM spikes reverberating through the global atmosphere also.

So we have a favorable setup to get some colder air back into the pattern after the weekend into early next week warmth. Will it be enough? Well, as mentioned, it gets tougher this late in the season, so all you can say is that it gives you something to watch for. Then we have to consider how long this pattern would last. Given the tendency of the atmosphere to want to jolt back toward the nina side of the AAM charts recently, the window of opportunity may not last long until we can say we are waltzing into Spring (keeping in mind up north can stay in the game into April).

AAM Tendency

Day 10 Model Forecast

March Comes in like a Lion

2009-03-02T11:40:00.006-06:00

March 1st marks the beginning of meterological Spring, though obviously the atmosphere is in full winter mode, moreso than it has all season long for some areas, in fact! For snowlovers in the eastern U.S, this has been quite a storm. While in some spots it was slow to really get cranking last night, many, especially in Virginia up to the D.C. / Baltimore areas, woke up this morning to more snow than they probably would have expected upon going to bed. But if you were tracking the upper level features of the storm, this should have been expected. I have a map of the 700 mb level (about 10,000 feet above sea level) below (first map), and have drawn in a red "L" to show where the upper low was located at this level with the storm this morning. The black arrow shows the approximate direction the low was tracking. The green shading shows the moisture content (specifically the relative humidity at that level). Notice the moisture along and the west of the track. It is in this zone where "surprises" can occur given a strong enough system. A common rule of thumb is that you want to be near or just west of the 700 mb low track, which worked well with this storm given how intense it was.

The second map below map is at the 500 mb level (approximately 18,000 feet above sea level). The colors here show vorticity, which is a measure of spin in the atmosphere. Ahead of strong areas of vorticity, called "positive vorticity advection", you have stronger rising motion. Behind them you have sinking motion, or "negative vorticity advection". With sufficient moisture in place, the lift from an incoming vorticity maximum (vort max for short) causes clouds and precipitation. I have circled the main vort max with this storm. The track of this feature was similar to that of the 700 mb low shown in the first map. So if you look at this map, you see the areas of greatest moisture content, which coupled with the strong vort max, led to bands of very heavy snowfall just to the west of the track of these features today. These bands typically can produce several inches of snow in one area, and very little not too far away, which is what I tried to show with the sharp cutoff in snowfall on the forecast map.

So hopefully you had a chance to not only enjoy the storm, but learn from it as well. The idea here is that even if a storm like this is a slow starter, don't ever give up on it if you are just west of the forecast track of the 700 mb low with a strong upper level vort max in play. You can often get a pleasant surprise in such a setup. Once the storm is totally done, I'll look at verifications versus the forecast issued yesterday.

Final Call for Snowstorm

2009-03-01T12:31:00.004-06:00

I pretty much outlined what all had changed and allowed this upcoming storm today into tomorrow to come farther west and up the coast in yesterday's post, so will keep this simple and just get to the final call map. The main thing is to tighten the gradient from 1-3, 3-6, and 6-12 zones. This ups the forecast to 6-12 inches in the big cities of the East Coast. You won't have to go too far though before amounts drop off quite a bit. As is always the case with these storms, confidence is lowest close to the edges due to the gradient. It will be cold and windy behind the storm too, with temperatures a good 15 degrees below normal (upper 20s to low 30s... teens for some interior areas in Northeast), so bundle up! Snow map below. Light blue is 1-3", darker blue is 3-6", and purple is 6-12". There can be local amounts to at least 15" within the 6-12 zone as well, though hard to pick out exactly where, so did not throw in a 12+ zone on the map here. Enjoy!

Quick! Man the Snowplows!

2009-02-28T12:33:00.007-06:00

Well, I mentioned how tricky this setup was for the upcoming storm, and while still, even this close to the event, there are some notable differences in modeling, I think things have definitely trended MUCH more favorable for a nice storm for many in the East, including places that have seen very little this winter. Let's go back to what we were looking at yesterday. I discussed how the key was an upstream "kicker" shortwave that was expected to move things along and push the bulk of this storm farther east. That had been the trend all winter long, and honestly, there was nothing suggesting that the northern stream would not continue to assert its dominanace, so that was the idea to go with. However, for the first time this season, things are trending slower / weaker with the northern stream flow, in that the kicker shortwave is weaker on today's models, along with a more solid ridge out west, and this allows the storm to come up the coast farther west. Let's look at a couple of maps. The first map down below is the GFS from yesterday, and I want you to take note of the shortwave in central Canada, highlighted in red. The second map is today's GFS, and look at how much weaker / farther north that shortwave is, which means less of a kicker, and BAM. That is a big key to all of this, and why models have come west, so please take a look at this. Now, you may ask. What about the NAM? This is the short range model that typically is the go to model at this range, and it is way east, showing virtually nothing for the big cities other than Boston. It is closer to what my thoughts were yesterday, so why do I discount it in this case? The reason is again because of the shortwave up in Canada. This shortwave this morning is up in northwest Canada, which is a location that I would tend to think the global models can resolve better than the NAM, and pretty much all models are lined up against the NAM at this point, which is tough to ignore. The final map below is my updated call, which as you can tell from this discussion, is a lot different than yesterday's guess. I'd also add that yes I can see a 12+ area in eastern New England, but wasn't confident enough to put it on here yet, so will call it 6-12 with local amounts of 12-16 and be done. I am going for a sharper precip gradient than the global models and perhaps still a little east of some of them. What can go wrong? Well, even at this short range, still a lot! The NAM could still score the coup, but we'll see if it shifts west any later today. Once the Canada features are more in the core of the NAM's grid, I would assume it does indeed pull west some. I won't be able to update the map the rest of today, since I will be out this evening, but will try to throw out last minute thoughts when I am able to. It does seem that if changes need to be made, it is more likely to be in the direction of increasing the amounts.

Weekend Snow Guess

2009-02-27T14:21:00.008-06:00

Will outline an update tomorrow with this...

I have to admit this is a very low confidence forecast, but it is time to take a stab. First, the model ideas. The European came pretty far west with the upper low, close to the Canadian, while other models are farther east. This is because the Euro / Canadian are slower with the "kicker" that helps push things along. Now, do we want to bet on a SLOWER northern stream in this winter season's pattern? I don't, and think the Euro has probably come too far west, as GFS seems to be initialized slightly better, but we'll see. It is a tricky call since we have a front running wave ahead of the upper low. Because of this, I have two maps. One for the front runner and another for the upper low itself as it moves across. I also need to point out these maps are for snowfall ideas. While I have wave one missing the big cities with respect to acumulating snow, I do think sleet is very possible, especially from Philly to New York, and perhaps Boston as well, though some snow should fall there. I'm not as emphatic with this front wave as the NAM model, but don't mind its overall track.

The second wave with the upper low itself, unfortunately may wind up too far east to help the big cities, as I don't think it phases, but rather gets pushed out to see faster than what the Euro / Canadian alliance show. D.C. is the toughest call here if I am right with this overall idea, and I have them near the 1-3" boundary. This looks like a great storm for western North Carolina, and we may actually get a decent snow in the Roanoke to Richmond corridor (if this fails I will give up predicting snow ever there hahaha). The reason this is all so difficult to pin down is because you have to assess how quick the cold air arrives, then how far east the front wave pushes the boundary, followed by the position of the upper low and how it interacts with the boundary left from the front wave. Here are the maps. First one is for the front running wave tomorrow evening into Sunday. The second is with the upper low Sunday into Monday. If you'd like any clarification, by all means ask. If this busts, I think it will be due to a less impressive first wave, and a beefed up wave associated with the upper low. The interior Southeast could do better than what I have here, especially near mountains.

What a Mess!

2009-02-26T17:45:00.002-06:00

Well, we are within 3 days of the weekend event, and there is still so much to resolve. Part of the reason models (and forecasters) are struggling with this event is because there are so many shortwaves playing a role in the evolution of this storm, and according to most models, these features are unable to consolidate into one potent system, so we wind up with a couple of different waves developing along the frontal boundary that moves through on Friday. Getting back for a moment to the original 3 scenarios I outlined the other day, the closest to what looks to be happening is number 3. The northern stream features actually do look to be progressing a little more than the Euro model from the other day showed (no shock there since this happens with seemingly every system this season). And also the southern piece more or less stays south and gets pushed out to sea too much to help most folks. However, the new wrinkle in this is that even the southern stream piece itself is divided, and some models show the leading piece in the southern stream hooking up with the frontal boundary in time to bring a wave of snow (and sleet) from the Apps up into the Northeast, while the second piece hangs back and could become a notable late season wet snow event for the Southeast. I think at this point it is hard to argue completely against the divided southern stream pieces, but I do wonder if models are jumping on wave number one a little too much and thus not developing the core of the southern upper low enough. The UKMET model seems to be putting more eggs in the basket of the second piece, and to me isn't unreasonable as far as modeling goes. We'll know more though tomorrow once all of the players involved are squarely in a location where they will be able to be better sampled by upper air data and thus better handled by models.

If time permits, I'll throw out a forecast map for this event tomorrow. Right nowI think folks near the Apps and up into interior Northeast are fair game for a decent late season wet snow event, all the way down into the Carolinas as well as eastern Tennessee and northern Georgia. And the upper low is strong enough that even some lower elevations farther east in the Carolinas may see some accumulating wet snow out of the deal.

What about the big cities of the East? I can envision precipitation staying mostly frozen from Boston down to New York City, and maybe even Philly. This could be quite a sleet-fest in these areas given the strength of the low level cold currently up in Canada, which always proves tougher to get rid of than models think, so while it may not be a big snow event, it could be reminiscent of the sleet events from a couple of winters ago, thus still a notable late season storm.

I'd like to be able to offer more specifics, but having been out of town the last few days, that makes it tougher to dive right in and try to figure out things with such a complex setup like this one. Again, hopefully I'll have a map tomorrow to show visually what I think is most likely.

Weekend Update

2009-02-25T12:28:00.002-06:00

Just a quick note here. Looks like the weekend system talked about in the previous post has developed into more or less a "two wave" feature. The southern piece (again discussed in previous post) did trend a little farther north, and doesn't look to have enough cold air around to help many folks outside of the Appalachains and interior Northeast. To be sure there can be a few inches of wet snow here. With it a little farther north, that allows the northern stream feature to dive in behind this system, and though it doesn't looks like it will "phase", it does have a chance to initiate a second low offshore, and depending on track, this could enhance more snowfall in parts of the Northeast. I'm headed back home today, and tomorrow can focus on how much snow will fall and pin down location better. This is just a brief overview on where things seem to stand right now, which is all I have time for currently.

Another "Fantasy" Storm for the East? Or the Real Deal?

2009-02-23T17:49:00.008-06:00

Checking in on the weather from my perch in Denver, Colorado, I see we have another potential storm threat to disect for 5-6 days from now, for this weekend, in the eastern U.S. Once again, among the major computer models, it is the European blowing the horn loudest (what in the world happened to this model?). I'll post a couple of maps here, but I almost feel like my analysis resembles a broken record, as the same concerns exist for this possible storm that have existed for every threat this season. Anyway, here is the Euro's upper air map for Saturday morning:

I have drawn in a few features here. The red line in the middle of the U.S. is the feature that is our possible storm. I also drew in two other shortwaves in the northern stream up north, and the blue arrow is the northern stream itself. Notice the southern piece has "detached" from the northern stream flow. That allows it, according to the model, to slow down and "cut off" in the East, turning into a potential big late season storm. Here is the forecast map for Sunday morning off the Euro model:

The same features are outlined, and you can see the northern stream is still well north of the southern piece that it cutting off in the East. This is not something that has been able to occur all season, and frankly should not be trusted here. I see three scenarios here, and 2 of the 3 basically turn this into a non-event as far as any chance to turn into a large snowstorm.

1) The Euro model is right and we get the storm, as it is able to detach from the northern stream and cut off in a perfect position with just enough cold air... again leaning against this right now though

2) Look back at the 1st map, and note the shortwave (in red) almost directly north (actually north-northwest) of the system that is supposed to become the storm. What if the flow is again going to verify faster, and this piece is a little farther east, and can drop down and merge with the southern stream feature (most recent GFS actually showed this)? Then you get a system that cuts inland and brings rain to the East, though could be a nice snowstorm for the Great Lakes region.

3) The flow is faster, but we don't get the merging of systems (or phasing), so the southern piece is free to slow down. But the dominant northern stream crushes any ridging in the Rockies more than the Euro shows, thus any cutoff in the eastern U.S. is weaker and farther north (disconnected from major cold air source as well), or just gets pushed out to sea. This solution might be able to bring some wet snow in some localized area, but wouldn't be a huge, widespread system.

Not to play Debbie Downer for snow lovers, but it is hard given the pattern to go against option 2 or 3 here. It will take almost perfect timing to get the actual solution shown in the maps above, or something close to it, to verify in my opinion. But again, any sane forecaster must throw in the fact that this is still a few days away, and in meteorology, anything can happen.

Rocky Mountain High

2009-02-22T18:04:00.003-06:00

I will be leaving for Colorado tomorrow morning, preparing to attend a workshop Tuesday hosted by Ed Berry and Klaus Weickmann. We'll be getting into global drivers of weather patterns, specifically with the "global wind oscillation" (some of you may have heard of this), in an attempt to improve forecasting going out 2-4 weeks. It should be a very interesting experience, and of course, getting a little trip out of the deal in a scenic area is pretty cool too.

I'll be doing a review of meteorological winter soon, which ends with the conclusion of February ("meteorological" winter covers the months of December to February only, as they are, on average, the coldest three months of the year. There will be a lot of interesting and unique things to discuss, some of which may be covered in the workshop as well. There were several "la nina" influences on the season, but we managed to get quite cold in many areas in January, which wasn't expected by the vast majority of forecasters, and this has certainly skewed the winter to the colder side in much of the eastern U.S, though the Southeast, in typical nina-like fashion, has been warmer than normal. I have posted below a map showing the temperature anomalies for this winter so far, which won't change much with only 6 days left until the end. Now we move on to Spring and severe weather season, though of course will still watch for any late season snow events as well. Image below courtesy of MDA.

Final Clipper Guess

2009-02-21T13:27:00.003-06:00

I'm working from a computer with no good map making software, so will have to put it in words. Looks like the transer of energy to the coast will come far enough south to allow snow farther down into parts of southern New England than where I had it the other day. Boston is a very tricky call but I think will get up to a couple of inches out of the deal in the city as heavy precipitation moves in even though temperatures look marginal. Lots of bust potential here though in both directions.

So here's my last guess:

2-4" for all of Massachusetts west of line from Franklin to Boston, perhaps down into parts of northern Connecticut.
4-8" from Worcester to Portland, Maine westward to the New York border (includes all of New Hampshire / Vermont
8+" for central / northern Maine, much of New Hampshire from Concord northward, and Vermont north and east of I-89

Clipper Update... March Severe Weather?

2009-02-20T12:01:00.013-06:00

Overall I'm still okay with the clipper ideas posted yesterday. I think the general areas I outlined with a shot at 2-4 inches of snow from the clipper itself isn't bad, though the area of highest uncertainty is in the state of Massachusetts. If the energy transfers to the coast farther south, then my areas would need to come south some at least in the East, as the low levels of the atmosphere would not be able to warm as much. It's a very close call to be sure for places like Boston. Also keep in mind my map wasn't meant to include any lake effect or upslope mountain snow behind the clipper.

I'd also like to look ahead a little to March here. There is not great model agreement in extended time frames, but the pattern presented by the GFS (American model) in early March would be quite conducive for some early season severe weather in parts of the U.S. Hard to say it is right yet, but it cannot be ruled out given the angular momentum drop recently and the overall nina-like tendencies this season. Anyway, just more of a "heads up" for now. Here are the upper air anomalies forecast by the GFS ensembles for the 11-15 day period (taking us to early March), courtesy of MDA Federal's site:

You can see all the negative anomalies out in the West, indicating a much stronger trough, or upper level storm out there. In the Spring, these can become prolific severe weather producers when they eject into the middle of the nation. To compare, I also have a similar map that covers some of the most active tornado seasons of the past. This next map covers April - June periods, which is the heart of the tornado season, but you can see it is very similar to the first map, indicating a favorable period may arise earlier this year, again if the GFS model is correct, which remains to be seen. We'll watch this potential over the next week or so, along with searching for any more notable threats for late season winter weather.

Weekend Clipper Snow Idea

2009-02-19T13:27:00.003-06:00

I figure at this point, despite how awful the computer models have been lately, I can offer an idea for the snowfall from the weekend clipper. It comes Saturday and Sunday, so of course there can still be large errors 3-4 days out, but why not take a stab. The big coastal storm idea of course is still gone, but this may develop strong enough to give parts of northern New England a good snowfall. This idea is shifted a little north of where I had the original lines drawn (not really "drawn", as I didn't have a map of course, but where I stated they would be). I'm highlight only the areas I feel have the best shot at 2 or more inches here from the clipper itself, not from lake enhancement or upslope snows in the mountains in the cold air behind the storm (to be sure that will accumulate too, but I consider that a separate, post clipper event). So keep that in mind when looking at the following map. You will notice I have a break in the 2+" snow potential in New York state, where I think there may be a "dwindling" as energy gets transferred to the coast and away from the primary low / batch of precipitation.

I will adjust if anything notable changes in the next day or so, and maybe tomorrow we can get into what lies ahead next week (European model making some "rumblings" again, but that has been an awful model lately). As always, click to enlarge and view my astounding map-making skills! Ha!

Progressive Pattern = No Big Weekend Storm

2009-02-18T12:43:00.002-06:00

I'm not sure what is trending lower... the stock market, or the chances of a big coastal storm this weekend with snow for the East. Both are looking pretty ugly now. As expected, the big storm shown on yesterday's Canadian and European models has vanished today. The progressive nature of the northern stream still keeps fighting off the chance for a deep snowstorm to develop. Having said that, we still do have the clipper coming in this weekend, which again, isn't a huge system, but does have a chance to put down a few inches somewhere as it moves eastward. My idea on this from the other day was that the best chance for more than an inch of snow ran from along and north of a line friom Muncie, IN to New York City. The adjustment I'm contemplating now is to move this line in the East more toward Boston, but let's see how things look tonight before changing that for sure, as four days out, that is essentially splitting hairs given how much things can change in that length of time. The northern edge looks to run roughly from Milwaukee, WI to northern Maine.

It does get colder in the wake of this clipper, but it seems milder air may arrive right at the end of the month and into early March. So while this cannot be said to be winter's last gasp just yet (it can still snow well into March and even April up north), we are heading for the finish line here in the next few weeks for most areas of course. I'll then await thunderstorm season, and use this space to focus on severe weather threats, and maybe a little educational stuff regarding global patterns / teleconnections and how they play a role in what happens here in the U.S. I'll do my best to fnd something of interest in the weather world at least!

A New Wrinkle in Weekend Threat

2009-02-17T13:26:00.002-06:00

If you asked me what I thought about the weekend clipper system today, again with a gun to my head, I'd still go with the ideas outlined yesterday, but a couple of models are really throwing us a curve here. There is no doubt that in this winter, nailing down details with storms has been very tough to do for pretty much every meteorologist and hobbyist that I know. Part of this I think is due to heading into a new long term regime in the Pacific, and the unique behavior of the sun and the stratosphere. I think all of these factors are really going to test folks in the coming years, and many people may need to refine their methods. We'll see. Anyhow, back to the present. If you simply adjusted for a faster northern stream and generally less amplification with storms (we did get some amplification and very cold weather in January), you'd be on target more often than not with these situations this winter. But now we have something unexpected. A couple of models, the Canadian and more importantly the European (typically more reliable) have indeed trended quicker with the northern stream, which makes sense with the huge drop in angular momentum and the shift to a nina-like pattern globally, but now they are so fast with the northern stream that the upper level system which brings the weekend clipper through splits, as the southern half of the upper trough cannot keep up with the momentum of the northern stream. This piece then forms a strong area of low pressure near the east coast Sunday, and since the clipper has gone through, there is fresh cold air in place. The end result is a large snowstorm for everyone from Virginia to the Northeast (central PA and western NY the cutoff on the western edge). So in a weird way, the fast flow actually helps out here. Now this is similar to what some models were doing a couple of weeks back when they showed a major Ohio Valley storm. As we all saw, that wound up weaker and farther east, and any adjustment like that here may kill the chance of a notable storm, even if the southern piece gets left behind. The key to breaking off the southern piece lies in a strong ridge that the Euro and Canadian models show in the Rockies, which leans northeastward into central Canada and helps force the split. If this ridge isn't as strong or positioned just right, you get no split or a much weaker one.

Bottom line... I have plenty of reasons to doubt this big storm idea right now given how this pattern has tended to behave this winter. But, as mentioned, this winter has thrown us for a loop before, so I will fully admit I could be wrong here. We'll have to see how the next few model runs go and see if my pattern expectations are off here (which I know most of you reading are hoping for hahaha).

By the way, what all of this also does if the European and Canadian models are right is bring about a colder pattern again just in time for early March as well after a warmup next week, so a lot is going on here.

Weekend Clipper Update

2009-02-15T13:15:00.008-06:00

Just a quick update on the weekend clipper here today. My opinion yesterday was that the computer model runs showing this clipper diving far enough south and strengthening enough to give a big snow all the way down to D.C. were overdone, and this would likely shift farther north as we roll forward, and probably a little weaker too. Well, today's models are all over the place. Some keep the farther south track, though much weaker, while others, such as the American (GFS) model are stronger with the system, but farther north. So what do we take from this? Well, at this point, from a modeling perspective, all we can take from it is that models really don't "know" exactly how this evolves, and need another couple of days perhaps to resolve all the features in play. What's my guess? If I had to make the call right now, I wouldn't be excited too much if I was south of a line from roughly Muncie, IN to Pittsburgh, PA to New York City as far as getting more than an inch or so out of this feature. I still have doubts that the northern stream will allow the big amplification / strong system to develop here that some models have been showing (for reasons mentioned previously), as systems in the northern branch on the heels of the clipper may be too close to allow for this to occur. But certainly we cannot rule out a moderate event in parts of the Northeast yet (along and north of the line mentioned above would be most likely candidates). We'll see how things trend now, as of course lots can change since we're still a few days out.

Clipper Threat for Next Weekend?

2009-02-15T13:15:00.004-06:00

The threat for significant snow out of the Thursday storm is gone for those not in Wisconsin / Michigan and over into northern New England, so on to the next possible threat. Last week I mentioned how the pattern is stormy and should at least give at least a couple of systems a chance to bring some snow. The next chance looks to be from a clipper coming out of central Canada. These types of storms that come from so far north usually aren't good for major snows, and usually wind up being threats more for the Great Lakes and Northeast as opposed to farther south, but there are exceptions. Anyway, some models now hint that this clipper will push far enough south to bring a snow threat into the Mid Atlantic as well as parts of the Northeast. In the wake of the Thursday storm, colder air comes back into the picture, so there should be cold air in place ahead of the weekend clipper. The issues then are 1) How far south can the storm "dig"?, and 2) How strong can it get once reaching the coast? When getting into a discussion about these questions, we cannot ignore the model errors this year, which as mentioned yesterday have tended to be underplaying the speed / timing of northern stream features. You see, once again, to get a clipper to dive southward, slow down, and strengthen big time along the coast, things have to work out just right, and that includes not having another system moving too closely on its heels to push it along more. I have shown the European model's depiction for next Saturday's setup, and again highlighted three features, with the one farthest east being the clipper storm. Now this model run keeps the systems spaced out enough, and does bomb out the clipper, bringing a big snowstorm to areas from D.C. to Boston. But what if the model once again underestimates the progression of the systems farther west (the other two I have highlighted)? If the model bias again comes into play, then the next two systems may wind up farther east and keep the clipper from digging as far south and getting as strong, and I would not be surprised to see that occur in subsequent model runs. So let's keep an eye on how the systems behind the clipper trend to see if this winds up being a legitimate threat for the Mid Atlantic states, or winds up being a threat just for the Northeast.

So What Happened to Next Week's Storm?

2009-02-14T10:56:00.006-06:00

As mentioned yesterday, the prospect for a winter storm next week in the eastern U.S. has greatly diminished. Back when this was first discussed, I said the key was getting the northern branch of the jet stream to slow down enough to allow the pattern to amplify and get a stronger storm far enough south to allow folks to get in on some winter love. It seemed a spike in global angular momentum might help us out (see prior posts for this), but that spike has waned and it seems that once again, computer models underestimated the northern stream. I will show you this below with a map that shows the European computer model's forecast for this coming Wednesday evening from back a few days ago when it showed a big storm, and compare it to the most recent run of the same model. For those who don't know what the map means, it's fine. You should still be able to see what I'm talking about based on the features I have highlighted. Here is the map from a few days ago:

I have drawn in red the three "shortwaves", or storms in the pattern embedded in the northern branch of the jet stream, that I want you to focus on. We have one east of New England, another in west-central Canada, and another almost off the map west of Alaska. I did not highlight the trough in the Midwest, but that was the system that is our storm itself. With this model depiction, it was arriving on the scene at just the right time, and things looked great, since the system east of New England would have colder air in its wake for the storm to "play with". But the issue, again, is that in this particular la nina-like pattern, the northern stream has very often moved along faster than models have predicted (there are reasons for this, but no need to get too technical here in this discussion), and if that occurred, it would kill the chance for the winter storm as 1) colder air could escape quicker, and 2) the storm can come much farther north. Sure enough, this is what happened. Here is a map off the most recent European model run, valid the same time, Wednesday evening.

I have highlighted in red the same three features in the northern stream, and because they are moving along faster than models showed a few days ago, notice how much farther east they are. Thus, any chance of the winter storm this week is no more, and we'll have to hope another one comes along and we can get a slower northern stream with better amplification into the eastern U.S. It's a tough chore in this winter.

I should add that this still doesn't rule out parts of New England from getting snow out of this storm, as of course it is colder up there and that may still be enough. This discussion is more about how the pattern just isn't cooperating farther south.

Dagger Inserted into Hopes of Next Week's Storm for Most Folks?

2009-02-13T12:39:00.003-06:00

It certainly looks that way. I mentioned yesterday how it looked like the pattern across the north (Canada) had trended less favorable, and that has continued today as well. Basically the flow is moving along enough to prevent sufficient "blocking" (which is the mechanism to trap cold air in the East and force an incoming storm to redevelop along the coast) for a winter storm to form. So it looks like the overall trend of this la nina-like winter will continue in this regard. This doesn't remove New England (probably interior) from the equation yet, but certainly farther south, this pattern just is not wanting to be kind to winter lovers.

What's next? Well, the bias of the pattern looks to be on the colder than normal side for many areas outside of the Rockies and the South from next week through probably the end of the month or even into early March as North Atlantic blocking may persist, and Pacific pattern stays favorable for colder systems to dive southeast out of western Canada, so the book certainly isn't closed on winter yet, but of course it is getting into its final chapters. At least with what looks like an abundance of storms tracking from west to east, there is still the hope that one will "connect", but in this year's pattern, it's going to have to "thread the needle", so to speak.

Quick Update on Storm Chances Next Week

2009-02-12T15:10:00.007-06:00

For my eastern U.S. readers, I figured I'd do a quick update here on the possible storm chances next week, specifically with the larger storm that has been showing up on computer model forecasts for late next week. Recall from yesterday the idea was that unless the northern brach of the jet stream slowed down, it would be tougher for the pattern to amplify, or "slow down" enough to allow a larger storm to develop. I did cite a couple of reasons why this could occur, one being the stratospheric warming recently, which has weakened the polar vortex, and the other being shifts in the tropical Pacific Ocean, which in technical terms, is leading to an increase in global angular momentum, which typically builds up as circulations slow (this can include the jet stream here in North America... It doesn't always happen this way, but can "stack the deck", so to speak). I have the angular momentum tendency below:

Focus on the bottom graph. You can see a spike up in the last week or two, but it is waning now. Computer models today still show the storm, but shifted well north of where they had it. This is a common adjustment especially with bigger storms, as stronger storms tend to form farther north anyway. But also the drop shown in today's angular momentum update may be a sign that hey, the jet stream isn't going to slow as much. That seems to be the message from today's models as well, as features across the north are shown moving along quicker and thus the storm isn't able to "dig" as much as previously indicated. The curious thing though is that models still show it blowing up into a strong storm, albeit farther north. I say curious because I would have assumed a quicker exit due to the faster northern stream, and a weaker low pressure as a result. This still gives me quite a bit of uncertainty with how this plays out. I certainly don't think anyone in the Northeast is out of the running with this yet. Down into the Mid Atlantic it's going to be tough, as you cannot ignore the trend of today's modeling, which matches the trend of the season for storms to generally trend north as time rolls on. I think the "la nina" tendencies of the pattern this winter have been the major culprit in this.

We'll see how things look tonight and tomorrow. If we can keep the "blocking" pattern that we have out in the North Atlantic / polar regions (which tries to keep colder air in place in the eastern U.S.), then this may not be the last chance for some winter fun, though it is getting late the farther south you live. Problem is timing how long until the block breaks and it is game over and we warm up (maybe a week or so into March?).

Severe Weather Verification... Winter Coming back to East?

2009-02-11T11:52:00.008-06:00

Unfortunately last night turned out to be a deadly one in Oklahoma, with at least 8 people killed by a tornado (I have heard maybe up to 15?) and many more injured. As far as yesterday's post and the area highlighted as the area under highest threat, it turned out okay... not stellar, but decent. I liked eastern half of Oklahoma and far Northeast Texas as far as greatest threat for tornadoes. There were only a handful of reports, shown by the map below, and it wound up basically right in the middle of Oklahoma with one in far north Texas.

Still have thunderstorm activity in the Ohio / Tennessee Valleys today, as well as into parts of the South, but the severe weather threat not as high as yesterday, certainly not as far as tornadoes, though it will be very windy even once the cold front associated with this system moves through later this evening.

This is a pretty exciting weather pattern though for weather geeks like myself... lots of storms to track from the West Coast all the way across the nation in the next week or two. The warmer pattern is about done (except for those of us in Texas, but meh, I'm fine with that). Winter weather lovers in the eastern U.S. may be able to rejoice next week and / or the week after by getting some snow out of the deal. Of course, most people would enjoy the big storm more than some nickel-and-dimers, and that isn't out of the question starting mid to late next week. To get a bigger storm to form, the jet stream across the north needs to slow down enough to allow for more amplification, and there are some signs that this may occur as the global atmospheric circulations slow in response to a recent stratospheric warming event as well as shifts in thunderstorm patterns out in the tropical Pacific Ocean (everything in weather is connected in one way or another). Some of the computer models we look at have shown quite a storm in the Mid-Atlantic late next week, and while it isn't uncommon to see computer models blow up storms way too much and too often, this pattern is a favorable one for above normal snows in many areas of the eastern U.S, whether with a "big one" or by multiple smaller storms. It's not a guarantee by any means, but at least suggests a higher than normal chance, which is all winter weather lovers can ask for at this point.

Tomorrow perhaps we can hone in on what areas are the ones to watch the most next week, tough as that may be from several days out!

Wintertime Severe Weather!

2009-02-10T12:07:00.007-06:00

Those of you not inclined to care about weather much may get bored with some posts here, or may not fully understand everything, but now that we are heading closer to Springtime, that means thunderstorm season is drawing closer, which personally is my favorite time of the year, thus I may focus on this more in the coming months. But it is also a time when people have to really keep a close eye on things, given that Spring is prime season for severe thunderstorms and tornadoes. These phenomena can occur at any time of year though, and late today / tonight may be one example of an "out of season" event, though we've seen more outbreaks in the winter season in recent years.

Today's area of concern is in central / eastern Oklahoma, northeast Texas, and over into Arkansas primarily. It's warm for this time of the year, and with a potent storm on the way this evening, may spell trouble. Predicting severe storms can be very tricky, as it is more a matter of how very small scale features interact with one another. But there are some large scale indicators that can at least offer clues as to more likely target areas. The first thing you need is to have a warm, moist air mass in place. Dewpoints ideally need to be in the 60s, which we should have in much of the affected area later this evening (take my word for it since I'm not posting a map of this here). Without this, there is not sufficient "juice" for a large outbreak typically. Warm, moist air is more "unstable", meaning it rises easier, and it is this rising motion the fules thunderstorm development. Next, consider this evening's modeled surface map of the southern Plains (click to enlarge):

The black lines indicate sea level pressure. The colors are temeprature. Winds are shown by the small wind barbs. Low pressure is seen in western Oklahoma here, with a value around 997 millibars (mb). A "rule of thumb" (in quotes because no "rule" ever works all the time in this business) is that, once you have established enough moisture (high dewpoints) in place, look for pressures of 1004 mb or lower. As you can see by this map, that covers most of Texas and all of Oklahoma. Next let's look at what's known as the low level jet. This is at roughly 5000 ft above sea level:

The colors here represent wind speed in knots, and again the wind barbs are shown to show the direction of the wind. Note the strongest winds (which is the low level jet) found in eastern Oklahoma and Texas, with speeds over 50 knots, which is well over what is necessary to generate severe weather. Also note the winds are out of the south or even southwest, whereas the surface winds in the first map are out of the southeast primarily in this region. This turning of the winds with height (wind shear) is a very key component especially in the formation of tornadic storms. Also keep in mind that if you are looking in the direction that the low level jet is blowing, the bulk of tornadic activity would usually be to your left, placing central / eastern Oklahoma and eastern Texas most at risk. Finally, to keep things sort of simply, here is the same map but for the upper level jet (now up 30,000+ feet above sea level):

There is a very strong jet here from central Texas northeastward into Arkansas and Missouri. So in looking at the last two maps, there is solid "coupling" (or intersecting) of the upper level jet and low level jet in southeastern Oklahoma and northeast Texas. Another "rule of thumb" is that when you have this coupling of the jets, areas near the region of intersection and to the left of the general direction the jets are blowing (again assuming you are facing that direction) is the primary point of concern, so given that sufficient moist air should be in place, tells me that the primary area to watch in this case is far northeast Texas and the eastern half of Oklahoma.

So we have a lot of large scale factors coming together for some rough weather this evening into tonight, with the most likely target for severe, possibly tornadic storms being in eastern Oklahoma and far northeast Texas, spreading into Arkansas late (the maps are static pictures, and of course all of this moves east and the night wears on). Keep in mind though I mentioned how important the small scale features really are, which I haven't gone into. This is more just to analyze the big picture and say, okay, here is the general region to watch for problems. We'll see how that goes. Hopefully everyone in the area is prepared just in case.

I may get more technical with some of the weather stuff in the future if enough weather saavy people check in, and heck, might be able to get back to true winter-like weather and talk about snow chances for the eastern U.S. soon!

President Pelosi?

2009-02-05T20:14:00.004-06:00

Sheesh it was painful even typing that title, as that is a thought that would scare the living heck out of me and any sane person. But after watching President Obama's speech tonight, I felt like I was listening to the whacko Speaker of the House (Nancy Pelosi) instead, hence the title. I have had hope that Obama turns out to be a good president, and up until tonight would have even given him a favorable rating, despite the less-than-stellar nominations he has made. Maybe I'm too nice of a guy. But after tonight's performance, what hope I had for him is gone. Why? Well, mainly because he came out and basically told the American people "What you thought I was... what I ran on... Sorry that is not what I am." He had a very combative tone. He is using fear mongering by making statements like this "stimulus" MUST pass or we may not recover (funny since he and his party always blasted the previous administration for using fear tactics). So rather than actually debate it, we're being told we have to rush through whatever he, Pelosi, and Harry Ried want or we will cease to exist as we know it. Oh boy. So much for bipartisanship. When discussing the pork-inflated "stimulus", and how much it costs, he barked that the massive deficit was there when he arrived. So that means you spend like there's no tomorrow and make it worse? Sorry Barack, no sane person can follow such "logic". And then there was his comment that "all big bills have earmarks (pork - garbage thrown in that shouldn't be there)". This is true, but all during the campaign he stated how he would fight to change this. Hypocrisy? Yep! I said there was an epidemic of this in Washington, and it has infected our President. He is clearly NOT going to be what he said he would be if this is the road he chooses to continue down, and why should we think he will do otherwise after such a shameful performance tonight? America voted for a change. This isn't an attempt to refute or ignore that. But the problem is, the change he promised is not the change being delivered. I hope I'm overreacting here just due to being pissed after listening to this, but I have lost a lot of what optimism I had, and honestly don't think the President has any clue how to fix things, so is caving in to the loons in his party. Change indeed. Buckle up America.

An Epidemic of Hypocrisy

2009-02-04T13:09:00.002-06:00

The more things change, the more they stay the same I guess. Despite a new administration in Washington, coming from a different party, it looks like all we are getting is more doses of "do as I say, not as I do." We had the Republicans, who claimed to be conservative, yet spent money as well as any liberals ever could. Now, we have thrown them out and have the Democrats... who have given us folks like V.P. Joe Biden. Recall, he thinks it is "patriotic" to pay taxes. That's pretty comical in light of all the Obama appointees who have turned out to not even pay all of their taxes! So apparently is it okay to increase redistribution of wealth, as long as it isn't your own, or at least that is the message here by some of these crooks, and yes, let's call them what they are. Now to be fair, sure, it is a small number who have been "found out", but you have to wonder how many more would turn up if audited by the IRS. When those who are put in place to lead cannot even follow the rules, well, you kinda have problems. It's not always easy to find truly genuine people in the world anyway. Unfortunately, it seems to be growing infinitely tougher to find any of them in Washington... truly an epidemic of hypocrisy.

The Groundhog Has Spoken!

2009-02-02T12:00:00.000-06:00

Groundhog's Day has come around once again, and as usual, the verdict is......

6 more weeks of winter weather! Sorry all of you who may be eager for an early Spring. Of course, this is for entertainment purposes only, but you would think they'd at least try to bring in some unpredictability to it. Anyway, the legend states that when he sees his shadow, that means 6 more weeks of winter, and when he doesn't see his shadow, it means an early Spring. But it really is a big joke considering that he has seen his shadow in 97 out of 112 years, so it seems more an excuse for the locals to camp out and get drunk watching a rodent crawl out of a hole, since the result is pretty much a forgone conclusion.

Anyway, maybe the result will have some validity this year. Not that it matters where I live since we don't have a winter season haha, but there are a lot of signals saying that, despite a break from winter weather for most of the nation this weekend into first half of next week, chances for cold and snow will return in the second half of this month for a good deal of the nation, and maybe into March.

Speaking of snow, the city of London had their biggest snowstorm in almost 20 years today! Somewhere though, Al Gore is still ranting about global warming. (Yes I know one snow event does not make a climate shift, so this is kinda tongue-in-cheek, but let's see how the next several years unfold... refer to my post awhile back for my viewpoint there).

Super Bowl Time!

2009-02-01T13:26:00.000-06:00

Yep, it's that time again for the most watched sporting event of the year. I'm typically more of a fan of college football than a fan of the NFL, but usually watch the Super Bowl regardless of who is playing, though it ends pretty late for those of us who have to be up at 3:00 AM the next morning. I'm not all that interested in this year's version, but since everyone else is doing it, here is my fearless prediction for tonight's game:

Pittsburgh 24
Arizona 14

Now That's a Cold Front!

2009-01-27T16:20:00.000-06:00

Back to weather for a bit...

We've had a few pretty strong cold fronts move through Texas this winter so far, and another one is on the way now (probably moving through before people read this)! I went for a walk earlier and it was almost 80 degrees, and humid to go with it... kinda yucky for late January. Hard to believe not far away it is over 30 degrees colder. It will be quite a change later this evening into tonight, with a temperature drop of around 40 degrees or more from now to tomorrow morning. This map says it all. Check out how close 70s (and even an 80 in Conroe) are to temperatures in the 40s and even 30s!

Tax Time!

2009-01-27T16:04:00.001-06:00

It's that time of year again, when hopefully we all can look forward to getting a refund from good ol' Uncle Sam. I've only recently been preparing my own taxes (yeah I admit I was just too lazy to do it before), and this year get to use the purchase of my first home to hopefully get a little extra cash back. As I've quickly learned, make sure to check carefully and claim every deduction possible to maximize your refund! Programs like Turbo Tax definitely make this much easier and keep you from making mistakes, that's for sure. But then again, we're going to put a guy in charge of the government's treasury department that can't even figure out how to do it right, so maybe mistakes do not matter, huh.

Happy deducting!

Living in the Past

2009-01-22T12:02:00.000-06:00

Obviously even the election of Barack Obama cannot allow some people to let go of the past. While a lot of focus was on Obama's decision to invite Pastor Rick Warren to be a part of his inauguration, we managed to get an old timer named Joseph Lowery chosen to deliver the benediction at the end, and proceeded to get a bit of nonsense tossed in at the end of his prayer:

"Lord, in the memory of all the saints who from their labors rest, and in the joy of a new beginning, we ask you to help us work for that day when black will not be asked to get in back, when brown can stick around . . . when yellow will be mellow . . . when the red man can get ahead, man . . . and when white will embrace what is right. Let all those who do justice and love mercy say Amen."

Excuse me? Now, it has been brought to my attention that this came from an old song or saying from back in the days of segregation. So that makes it perfectly appropriate to say... 30, 40, 50 years ago, but NOT now. It is sad that such a comment would be made on the day an African-American becomes the President of the United States of America. I guess white people helping a black man achieve such a goal is not considered embracing what is "right". Give me a break. This stuff certainly is not beneficial when it comes to further improving race relations.

Oh wait. According to Lowery, I guess relations haven't actually improved over the last 40 years after all. Silly me.

Oh By the Way... Banks Still in Crisis

2009-01-20T16:55:00.000-06:00

A little lost in all the inauguration coverage is what occurred in the financial markets today. While the focus is on the celebration of a new president, and a new hope for the nation, we have quite a crisis on hand here to deal with. To many, this isn't really new news, but I don't think a lot of folks grasp how serious this is. Bank stocks were just destroyed today, with big banks like Citigroup and Bank of America reaching levels not seen in over 15 years. I'm no expert economist by any means, but I do know investors are not stupid. These giants are still in huge trouble. The bailout (your tax dollars and mine) is a failure, and I don't think the banks or even some of the politicians are being up front about how big the problem is. It seems that nothing short of nationalizing these banks (gasp) will prevent them from failing... a big undertaking.

Moral of the story, the worst of the economy likely is not here yet, so the government had better try to come up with solutions fast, at least as best they can. Economies to a large degree are cyclical, and are going to have ups and downs regardless of anything the government does. In the meantime, let's all just hope we still have a job in a few months. I know I for one don't feel all that safe.

A Day of Change

2009-01-20T11:51:00.000-06:00

Stepping back from weather today...

The title of this post was the headline in today's paper here locally. Obviously anyone not living under a rock knows why, though the definition of "change" has been very generic if not totally unclear as far as where the nation is headed. But that part aside, one element of change is very evident today, and should be celebrated. We just inuagurated the first black man as the President of the United States (okay so he isn't 100% black but you get the idea). As I said to folks the day after the election, that is a very remarkable thing, which was thought of as impossible not too long ago. This is a very important moment symbolically for the nation, and hopefully will go a long way in helping to further ease racial tensions, though I realize only an extreme idealist would ever expect those issues to totally go away.

I'm a conservative, and did not support Obama, but on this day, regardless of where your beliefs lie, we should all be willing to put aside differences for a day and applaud our nation for coming this far. There will be time for criticism, if warranted, as Obama's four years unfold, but at least for today, partisanship should be put on hold.

What will the future hold? Who knows. But count me in with conservatives who, while not agreeing with Obama's point of view on many issues, still wish to see him and our nation succeed. As bad as things are now, we simply cannot afford more failures in the next four years, and wishing for this solely to have a reason to throw him out of office in 2012 doesn't make a lot of sense to me. And this goes for those who genuinely wanted to see Bush fail (there were plenty in this group). It is definitely the start of a new era... a new chapter for the United States. How will this new chapter be written? Stay tuned the next four years and we'll all find out!

Wild Weather Stats from Yesterday

2009-01-17T15:43:00.000-06:00

I mentioned yesterday how cold some areas of the U.S. were. For folks living in the Midwest who wanted to escape the warmth, you could have went up to the middle of Alaska. Say what? Yep, that's right. Amazingly, Fairbanks, Alaska saw a high temperature about 50 degrees warmer than the high temperatures in places like Chicago, Illinois and Columbus, Ohio. Normally, high temperatures this time of the year in Fairbanks are a degree below zero, but it was 52 there yesterday, but only 3 in Chicago! Pretty Amazing. Nature likes to balance things out, so when it is very cold somewhere, there will be anomalous warmth somewhere else to compensate.

Global Warming???

2009-01-16T10:42:00.000-06:00

As someone who forecasts weather for a living, I get asked a lot what my opinion is about global warming. Of course, today is a funny day to talk about the topic, as you won't hear much about this on a day when places like Chicago are seeing their coldest temperatures in almost 13 years (17 below zero!), and some places in Iowa set all time record lows (as much as 34 below zero!). That is cold!

Anyway, it has always been my view that a warming trend is pretty clear if you look at the data over the last 100+ years, as shown by this chart:

Focus more on the top chart, which averages the ocean and land, thus giving a true measure of the global temperature. It's pretty clear that the trendline is up from 1900 onward, so to me it seems silly to assert that we are not in a warmer world than what we were 100 years ago. The causes of this are what the real issue is. Obviously the media leads you to believe that mankind is responsible for "runaway warming" and thus we need to take actions to stop it before the world as we know it ends. Well, truth be known, all the junk we spew into the atmosphere probably isn't helping, and probably is responsible for some of the warming, but it is tough to say how much of it. Is it 90%? 50%? Only 10%? I personally believe that natural cycles are responsible for a good deal of the temperature trends, and may actually be pointing toward a cooling trend globally. Now there is something that may shock Al Gore and the mainstream folks! Anyway, I will make my case here, keeping things as simple as I can so as to not get too technical. The following graph is a chart of the Pacific Decadal Oscillation. Don't worry about what this technically is, as the important thing to know is that when it is negative, the Pacific Ocean is cooler overall, and when it is positive, the Pacific is warmer, and each phase tends to run 20-30 years (thus the term "decadal). This is a natural phenomenon driven in part by things like el nino and la nina, solar cycles, oceanic circulations, and probably other things we are not even aware of yet.

Notice how from the 1940s to the 1970s, this oscillation was negative. Then go back and look at the temperature graph above, and what do you know? The global temperatures actually trended down during that 30 year period as well, and once the Pacific warmed again after the 70s, the warming trend came back. But notice at the end of this graph, around 2000, changes began again, and the last few years have seen cooler trends in the Pacific once again, which is very natural and we were due for this. Now here is something else you don't see reported, which are the global temperatures since 1998, according to the Hadley Centre in the U.K.

Click on the image to see it clearer. You will see that the last few years have actually been trending cooler globally despite some of the global warming hysteria. Now, anyone who knows a lick about statistics will correctly point out that in any long term trend there are fluctuations, so we cannot use this to say for sure we are entering a period of global cooling, but assuming the cooler oceanic phases for the next couple of decades, coupled with a weaker sun (which I haven't even mentioned so far), it stands to reason that the warming should at least slow down, if not reverse some in the coming years. So yes, I do believe the doom and gloom predictions are mostly just a means to create panic and play on our fears. Oh the irony here. I should find the video clip where Al Gore rants about President Bush playing on our fears, when he is doing the very same thing with the whole climate issue, but who am I to argue with such an expert on the subject (sarcasm intended!).

So I am not a skeptic of global warming, as it has been occurring, but I am a very skeptical of those who claim they have the causes all figured out, as I have yet to read anything that invalidates some of the natural cycles I have mentioned here as possible drivers of climate change. Maybe it will turn out that they are right. I definitely don't have all the answers myself, but know enough to see that the debate doesn't appear to be settled. The next several years will be interesting to watch.

Having said all of this, I am 100% in favor of looking for cleaner / alternative energy sources because, well, spewing crap in the air isn't healthy for anyone regardless of any warming it causes or doesn't cause, and of course we cannot rely on fossil fuels forever, so in that sense I'm all for going green!

Memorable Headlines from 2008

2009-01-14T13:17:00.000-06:00

With the financial markets getting destroyed today, causing the resumption of chants of more economic doom and gloom on the way, it's time to look at something from the lighter side. Since we are still early on in the new year, it's not too late to go back and look at some of the more memorable headlines from the year 2008. Maybe you have seen some of these already, but either way, some funny stuff!

My First Trek into the Blog-o-sphere

2009-01-12T21:35:00.000-06:00

Well it has taken awhile, but I finally decided to create my own little space on the web where I can ramble on about whatever I feel like rambling on about. For anyone who doesn't know, my name is Brian, and I grew up in Virginia, but now work as a meteorologist down in Houston, TX in order to support my wife and my little boy (soon to be two children!). Trying to forecast the weather is certainly a fun but very challenging, and sometimes humbling job, since of course you have to accept that you are simply going to be wrong sometimes. Fortunately, the science continues to improve though, but the goal is to work hard to maintain an edge on the competition. Perhaps you do not think of weather forecasting as a competitive business? Take it from me, it can be extremely competitive, especially down here in the energy capital of the nation, where loads of cash can be riding on your forecast, meaning an accurate forecast is in very high demand. Anyhow, enough of that for now. While I will throw in weather related posts here, this blog will not be limited to meteorology by any means, but rather will serve as my place to discuss a variety of topics, from weather to money, politics, current events, or whatever crosses my mind. Everyone definitely has their own perspective on things, and mine will be presented here, when I'm not occupied with my job or entertaining the family (of course that comes first!). Enjoy!