First Tropical Storm of Season?

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!

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

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

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

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.