Thursday, November 06, 2008

TS Paloma: November 6 Update A

I know, it's difficult to imagine there's a Tropical Storm out there,
when here in Tropical Florida it is a chilly ~75 deg F... brrr... get
those woolly mittens out! ;)

TS Paloma was officially named in the middle of the night. She's now
moving NNW at 7mph, which means she's easily going to remain over water
and is currently centered at about 15.3N, 82.2W. Officially, winds are
40mph (TS: 39- 73 mph), but I expect that to increase during the day
today to at least 45-50mph - still a weak system. Central pressure is
1000mb. Another plane is scheduled to go into the system this
afternoon. Despite the weak winds, there are patches of strong
convection - mostly over water (including the Caymans and Jamaica).

Surface water temperatures are 28-30 deg C and soon she'll be moving
over waters that are over 26 deg C in the upper 100m of the water
column... this will keep her well fed and happy. From an atmospheric
point of view, vertical wind shear is now quite low and looks like it
will remain low for the next day or two. So really, there isn't much to
inhibit her intensification in the next 48 hours and I agree with the
NHC forecast. There's a very good chance she'll become a borderline
TS/weak hurricane as she approaches the Cayman Islands.

Interestingly the most reliable models diverge completely in terms of
intensification after ~two day: some say she will undergo rapid
intensification and continue on towards Cuba as an-almost major/major
(cat 3 or higher) storm, and others think that the wind shear will
increase which will decimate the system in the Caribbean. So the choices
for Cuba are - BIG storm or NO storm... (anyone looking for ideas for a
reality tv/game show?). You can see why it's tricky basing forecasts on
models sometimes. We'll know by Sat. which group is correct. I fall
somewhere in between the two, which is the tactic I think the NHS is
taking as well (but for different reasons).

The forecast track takes the center of the cone just left of the
Caymans, and then curves NE towards the center of Cuba and across to the
southern Bahamas. This might be a little too far right... currently it
looks like there's a chance it will pass north of the center of Cuba and
towards the northern Bahamas (if she survives). But again, that's 3-4
days away so things could change. (Folks in southern Florida should also
just keep a small eye on this system).

<Soapbox alert> Intensity forecasting is a very tricky thing (as it's
based on the track of a storm)... but you may be interested to know I
heard a talk last week that showed some improvement in a hurricane
intensity model - something that would help the NHC at least. I asked
why it wasn't being used as an 'experimental tool' by the NHC. I was
surprised to find out that it is very difficult for anyone outside of
NOAA (NHC is part of NOAA) to get something like that to people in NOAA
(and equally frustrating for people in NOAA who would very much like to
work with people outside NOAA). Now, you would think that for something
like hurricane forecasting where lives are at stake and beaucoup $ are
involved, they would at least make it easy to work together for a common
goal, right? My (very limited) understanding is that it's some sort of
an institutional block, not a person-to-person block. Since then I've
heard the same thing from a number of other people. But, the bottom line
that I wanted to let you know is that there are improvements being made
in hurricane models... they just may take years to emerge from the
dungeons. I hope you can wait. <end Soapbox alert>.

I'll send out another update later.

Toodle pip,

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DISCLAIMER: 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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