Monday, August 18, 2008

TS Fay: August 18 Update A

Ever had one of those lovely weekends when you get away from it all and
then come back and ease back into the swing of things? No? Me neither... ;)

I've been a little (just a little though) concerned for a few days now
that the center of circulation is not quite where the NHC says - this
has been such a weak system that it has been difficult to pinpoint the
exact center and they know that too, despite planes going into the
system to investigate. Part of the problem has been that there is
circulation at different levels of the atmosphere, and they don't all
overlap exactly as you see in a classic image of a hurricane. This is
often the case with weak storms and is part of the disorganization in
the system. Another part of the problem is that the heaviest convection
is to the east of the center (and now to the north as well). She's just
exiting Cuba now and already interacting with the Straits and therefore
gaining strength. As she gets stronger her center will emerge. At the
moment it really looks east of the track they have her on and if that's
the case. either they had it in the wrong location, or she's taking a
more northward track than they forecast - both are likely in my opinion.
Her official center is somewhere around 23.3N, 81.2W. I think she's
perhaps closer to 23.3N, 80.9W. As I expected, the computer models that
were heading north and west have shifted south and east.

Track: The last advisory had her on a NNW heading at 12 mph. The high
pressure system that had her moving westward for most of the past few
days began eroding yesterday, so she began to make that NW turn... and
from what I see it has eroded further which allows her to move a little
more northward now. I will get the latest pressure fields in a couple of
hours, so I'll see how much it's really eroded, but she is moving
clockwise around that high pressure. Currently the western edge of that
high extends over the southern tip of Florida - the next fields will
show me if it's holding steady there or eroding even farther eastwards.
So from the pressure fields at the moment, it looks like landfall in the
upper Keys and then up over central Florida, exiting somewhere on the
eastern side - possibly northeastern Florida. We should have a better
idea today (obviously). I trust everyone is getting ready or is ready? I
know that folks here are making plans.

Actually, using the best technology at my fingertips, the track she'll
take is here:

Intensity: She'll be crossing the warm waters in the Straits of Florida
- over 31 deg C. The warm waters of 26 deg C extend down to about 75-80
m, which is deep, but not as deep as it was south of Cuba. Wind shear
is low, and remains low ahead of her. So I can see her intensifying
today, and agree with the NHC on hurricane strength on landfall. As of
the 8am advisory, her max. wind speed was 60 mph which makes her a
mid-to-strong Tropical Storm (TS wind range: 39-73 mph).

More after the 11am advisory... now I'd better go and get some water... ;)

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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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