Tuesday, September 12, 2006

Hurricane Florence & Tropical Storm Gordon: September 12, Update A

"Hurricane" Florence:
The 5am advisory said that Florence was still a cat 1 hurricane with
winds of about 75mph. Cat 1 storm winds: 74-93mph. So it's nominally a
cat 1 and that wind speed is within all sorts of error margins
(instrument, satellite algorithm etc). Since then, this storm has fallen
apart even further. Cloud tops are much warmer and there is dry air in
the center of the storm. I consider this to be a Tropical Storm, and it
was probably a TS at 5am too, but as I mentioned for umm... TS Ernesto I
think, it is the NHC's job to be conservative and that is o.k.

I do not see any reason why they would keep it at the cat 1 designation
at the next advisory (11am). I will send out a brief note on this once
it gets officially downgraded, but other than that, this is my last real
update on Florence.

Tropical Storm Gordon:
Cloud tops in Gordon are actually colder than for Florence. He is much
smaller in areal extent compared to Florence. I agree with the forecast
track, which takes this out to sea. The good news for Bermuda is that he
will pass to the east.

As with most TS, I can't see a well defined eye. Wind speeds were last
noted to be about 60mph (TS range: 39-73mph) so this is a mid-intensity
TS. He is currently over water temps of about 28 degc C (minimum temps
required for tropical cyclogenesis is 26 degs C - tropical cyclogenesis
means 'development of a tropical system'), but given the track and speed
he is moving on, he will move over cooler waters (about 26-27 degs C
temps) within the next two days, which is enough to sustain the system,
but not really help to develop it further. However, he is in a low
shear environment at the moment and although there is dry air around the
system, I don't see it being entrained. So I think this will intensify
to maybe a strong TS/weak cat 1 and that's about it. This is
more-or-less in agreement with the NHC forcast. I'll only send out one
update a day on Gordon unless I see anything unusual.

That's all for now folks. :)
These remarks are just what I think/see regarding tropical storms (my
storm blog). If you are making an evacuation decision, please heed your
local emergency management and the National Hurricane Center's official
forecast. This is not an official forecast.

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