Thursday, September 3, 2009

T.S. Erika

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.

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