Friday, November 06, 2009

TD Ida: November 6 Update A

Oh dear, what a palava! I can just see some of you rolling your eyes when
you see the latest track and the apparent sharp right turn Ida is forecast
to make in the Gulf in five days, directly towards Tampa Bay. The forecast
has, indeed, become all sorts of complicated since yesterday.

First though: she's just emerged into the Caribbean again, north of
Honduras, and is heading N at about 8 mph. She's at 15.7N, 83.9 W, central
pressure 1007 mb, wind speed 35mph. Due to minor technical difficulties, I
can't actually access the data or satellite images. But I can tell you
what to expect.

As she continues north, she'll be over water temperatures greater than 30
deg C. V. Warm!! Not only that, but the warm water is very deep there -
amongst the deepest warm water in the western Atlantic/Caribbean/Gulf
region. This means she has a really good energy source because she's
churning up more warm water. The other factor in favor of development is
that the circulation remains strong over most of the troposphere. So it is
likely she will get stronger once she clears land - definitely back to TS
at least (in agreement with the NHC). Working against this is the wind
shear, which will pick up as she moves northwards. The second factor
against too much development is how much she will interact with land. A
battle will ensue over how strong little Ida will become.

The reason the forecast is a bit wonky in the Gulf is because in addition
to the uncertain intensity factors above, there is another front (trough)
that will move southwards at around the same time as she moves northwards.
It's a question of where the two meet, which is difficult to forecast.

Ida's a tricky one! Not what you want to hear I know. It's unlikely she'll
be a major storm *if* she gets to Florida. It also looks unlikely that
she'll head to the northern Gulf at the moment, but that depends on how
far south that front gets. For now you know the drill. It never hurts to
be prepared: stock up on ice cream, wine, sun screen etc. ;-) Drop me a
line if you have any questions.

As famously said in 'Terminator' by that bloke, "I'll be back". (tomorrow
sans technical difficulties).

DISCLAIMER: the views expressed today were so waffly that I don't think
anyone I represent (myself included) could possibly claim them! Pay
attention to your local emergency manager

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