Friday, September 22, 2006

Hurricane Helene: September 22, Update A

She's picked up forward speed and is racing along at 21 mph now...
heading in the general direction of north Scotland (but that's still
days away). She'll be an extratropical system by then.

Her winds are at 85mph, so she's still a mid-strenght cat 1. But I
really expect her to weaken soon (24 hours) because more of the system
is in a stronger wind shear, she's moving over colder waters (25-26 degs
C), and dry air is being entrained into the system. As a reminder,
waters of 26 deg C are needed to sustain a tropical system (but not an
extratropical system). Her slight increase in wind speed since
yesterday's 80mph was from atmospheric effects, not because of the
ocean. The southern and western sides of this system looks pretty
ragged. The circulation in this storm is still quite strong, so she will
be a nice extratropical storm soon.

If you look at a satellite image of her now
( you can see a long
arm of clouds extending to the north. That was a low front that moved
westward (across the US and into the Atlantic) and has now interacted
with this hurricane.

That's all for today folks (unless the next system out there becomes a TS).
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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