Tuesday, September 28, 2010

Tropical Depression 16: September 28, Update A

Well I must say that was lovely ... a whole day off! Gosh. What a luxury!! ;-)
So we have one pesky little blobette out there in the Caribbean, huh?  It may be the future Nicole, but I'm not very convinced of that. The NHC upgraded it to a Tropical Depression earlier today, and for once I must say I approve of this and their reasoning! It's a good spot to put it in becuse this is a funny little thing - not quite a Tropical or Subtropical Storm in structure, but not quite a front either. And it formed in a topsy turvy sort of manner. The word on the street (amongst the hurricane hommies - ooh... band name? ;-)) is that this is something that is more frequently seen in the Western Pacific, and is a monsoon-sort of system which may or may not develop into a tropical storm. It's not often we see this in the Atlantic. But this has been a topsy turvy sort of tropical storm year across the planet, with more storms in the Atlantic than in the Pacific. Usually the Atlantic is the slow one! I don't really watch the other basins as intently as I do the Atlantic (because I don't have enough hours in the day) so I'm afraid that for now it's a bit out of my realm to talk about monsoonal systems and whatnots in the Western Pacific. I'll see what I can dig up for some future quiz!
This Tropical Depression is still a blobette at heart and has more ferocious looking convection (rain, thunderstorms etc) than wind speed. It is officially centered at 21.4N, 82.0W, but it covers such a broad area of circulation that it's a bit tricky getting a good handle on that 'center'. It is moving NNE at 8mph. A minimum central pressure of 997mb was observed by Hurricane Hunter planes (again this was over a broad area) and the maximum winds are 35mph. BUT, because this isn't a Tropical Storm, the strongest winds are actually about 200 nautical miles southeast of the center. Southeast is also where the heaviest convection happens to be - the strongest thunderstorms, heaviest rains. 
This TD is looking a bit lopsided - the official center of circulation is to one side of the heavy convection. The track takes it over Cuba and on to Southeast Florida - this is along a low pressure front that has also been responsible for dumping rain over the Carolinas. There will be rain over the next few days - the Caribbean islands are already getting drenched. I haven't seen the little Cayman Islands all day, and Jamaica is really getting some severe thunderstorms at the moment! In the US, get your wellies and brollies ready... and possibly your canoes too! ;-) Parts (all?) of the southeastern seaboard have already had some rain from the front that is attached to this, but there will probably be quite a few bucket-fulls to come. The forecast has it as a Tropical Storm within a few hours, as it gets to Cuba, and then all the way up to North Carolina. I don't see it becoming a Tropical Storm as it crosses Cuba (the convection will decrease as it crosses that land), but there is a possibility that it will become a bit better organized as it moves over the Florida Current and Gulf Stream, after leaving Florida. Of course by then it might be completely part of that low pressure front and not a Tropical Storm at all! I also think it might be going a little east of the center of cone track, but it doesn't really matter because, if anything, this is mostly going to be a rain event for people in the US.
Until tomorrow, 
A bientot! 
Blog archives at http://jyotikastorms.blogspot.com/

These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and the National Weather Service announcements. This is not an official forecast. If I was there and was going to "run away, run away" (Monty Python), I'll let you know.


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