Wednesday, September 09, 2009

Hurricane Fred: 9/9/09 Update A

Fred became a major hurricane (cat 3) this morning, with winds of 120mph
(cat 3 range: 111-130mph), but has decreased in intensity since then.
Although the NHC's 5pm advisory still had him as a cat 3 with winds of
115mph, I think he's a cat 2 at the moment (cat 2 range: 96-110 mph)
because his eye is not very clear anymore, and the convection is a bit
skewed. His western side is a little weaker than the east, because he's
pulling in (entraining) dry air from the north and west. Also, his
northern side is beginning to move into an area of stronger wind shear.

He's currently centered around 14.8N, 33.3W, with central pressure of
960mb. The NHC had an interesting tidbit in their write up earlier
today...according to their records this is the strongest storm to have
formed so far south and east. There are a few caveats you should keep in
mind if you hear this: 1. Hurricane records only began in 1851; (2) a
storm like this would probably not have been detected before the 1970s,
when satellite observations kicked in and there are more, and different
types of satellite data available now which allow for greater accuracy
(hopefully!!); and, (3) techniques to estimate the winds and pressure of a
storm from afar have changed a bit over the years.

He's moving NW at 13 mph. I'm going to rely on the models and NHC for
track for the next 24 hours because the models are in pretty good
agreement at the moment and unless you are a mid-Atlantic jellyfish
<insert creature of choice>, I don't think small variations in track
forecast will matter. :)

Wind shear increases at about 18N, although sea surface temperatures will
still be over 27 deg C at that latitude. I agree with the NHC that the
shear will take it's toll and reduce intensity. But they claim a secondary
effect will be the reduced sea surface temperatures, whereas to me a more
likely secondary effect will be the surrounding dry air.

Famous Fred quote of the day: "Let's split up gang." Which Fred? :)

Night night,
J.

Disclaimer: Insert from previous entries.

1 comment:

Matthias said...

That'd scooby doo-fred.