Wednesday, September 26, 2007

[Jyo_hurricane] TS Karen, TD 13, and the Florida Blob: September 26, Update A

This is like a box of chocolates - there's an assortment of things out

Tropical Storm Karen:
As expected, she has strengthened and is now close to hurricane strength
with winds of 70mph (Cat 1: 74-95mph, 64-82kt). The deep convection has
just decreased, but that's just a temporary blip and not a long term
decrease, so we might see Hurricane Karen by the end of today. She is
over waters warmer than 28 deg C, but is in a region of reasonably
strong wind shear so that might help to keep the intensity down for a
while. As for the track, the pressure maps show the high that has been
steering her westwards is a little weaker. I can see the low that is
supposed to erode the high, but the question is will it happen before
she gets close to the Caribbean. Some models say yes, others say maybe
not. For now, I would say she'll stay on a west-northwest path for the
next 24 hours, which is more westward than the official center of cone
forecast. There is still room and time for her to stay in the Atlantic,
but I would still be prepared on the islands (don't put your rain gear
away yet :) ). She's plodding along at 13 mph, and will take another 5-6
days still to get to the Caribbean vicinity.

Tropical Depression 13:
The blobette that was hanging out over the western Gulf did a little
wonder woman swirl (which is going to be really embarrassing for it
later if it gets the manly name, TS Lorenzo) and re-emerged a bit
farther south (still in the western Gulf) as a tropical depression -
close to a tropical storm. The high pressure that it was stuck against
intensified southwards, so this system is still more-or-less stuck and
is drifting southwards at a grand 2 mph - the only reason we know this
is because a Hurricane Hunter plane was in the system this morning to
check if it was a storm, and will go in again this afternoon to check if
it is a TS. It is a very weak system, so it's tricky finding the center
of circulation from the satellite imagery. The models all have it going
south-southwest. It looks like there was a couple of millimeters of
Mexico that didn't get rain from earlier storms this year, so this
system might head in that direction. It's over warm waters and the
longer it stays there, the greater the chances for intensification.
Circulation for this system is in the lower to mid-levels of the

South Florida Blob:
The blobette that did not have much circulation to speak off over
southern Florida yesterday is now over the Straits of Florida region,
and has circulation in the lower and mid-levels of the troposphere.
There is more circulation in this system than there is in TD 13. There
is also a nice amount of convection associated with this system but the
center of circulation (southwestern Florida & Straits) is to the west of
the area of convection (southeastern Florida/Straits/Bahamas). It's
worth keeping an eye on this blob, particularly because there is
circulation, and because it is over the deep warm waters of the Loop
Current-Florida Current-Gulf Stream system.

Just as an aside, the official names for the Straits on either side of
Cuba are the "Straits of Florida" and the "Yucatan Straits". I have to
point this out because it drives one of my colleagues bananas when he
hears things like the "Florida Straits". Of course, if you want to see
him go bananas, now you know what to do. :)

There are other things out there, but nothing worth really writing about
at the moment.

Stay tuned... (or not) :)

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 "run
away, run away" (Monty Python), I'll let you know.

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