02 September 2004

Frances pounds the Bahamas, eyes Florida, 9th Depression of the season forms...

From Jonathan Vigh: 
The 9th Tropical Depression of the season formed this afternoon a few
hundred miles southwest of the Cape Verde Islands. This system came off
Africa a couple days ago and has possessed deep convection for at least
the last 36 h. Healthy outflow was spreading out in all directions even
before the system received a number, and it appears to be in low shear.
Its relatively low latitude and a lack of any immediate troughs will
allow this system to traverse the Atlantic fairly undisturbed for the
next 5 days. The official forecast calls for a 70 kt hurricane near
Barbados in 5 days. 

At 21Z, Tropical Depression 9 was at 9.7N  29.1W, moving towards the
west at 17 kt, with winds of 25 kt and an estimated central pressure of
1009 mb.

Meanwhile, Hurricane Francis is currently rampaging through the Bahamas
and targeting the central Florida east coast. The storm's southern
eyewall passed a little to the north Grand Turk Island in the middle of
the night. Sustained winds were clocked at 79 mph, which caused damage
to roofs trees. An hour or two ago, the eye passed directly over the
small, but populated island of San Salvador. Winds rapidly climbed to a
sustained 114 mph (with higher gusts). Long Island is next, followed by
Cat Island and Eleuthera (this island was strongly affected by Hurricane
Andrew in 1992). Unfortunately, nearly all the Bahaman Islands will be
affected by this storm. About 300,000 people live in the Bahamas, and
nearly all of them are going to experience some portion of this storm
(it is hard to evacuate from an island for obvious reasons). 

Frances weakened somewhat this morning, with the central pressure rising
to 949 mb. Winds have decreased slightly to 120 kt. There was an
apparent disruption to the eye, which was open for a while this morning.
Perhaps this was another eyewall cycle, or even a bit of vertical wind
shear. The appearance on satellite is not quite as good as in recent
days -- the storm is a little ragged and somewhat asymmetrical, but very
deep convection is still blowing up in the eyewall. With continuing low
shear, extremely warm Gulf Stream waters (as warm as 88 deg F along the
coast!), and less dry air in the environment, there is at least a chance
the storm will strengthen before landfall. More eyewall cycles could
cause weakening, but it is highly likely that Frances will hit as a
major hurricane.

Where will Frances hit is the next question to answer. The global and
regional models used by hurricane forecasters have tightly clustered on
the central Florida coastline. The most likely place to experience the
core of the storm is anywhere from West Palm Beach up to Vero Beach. But
the storm could still hold surprises in the track department (remember
Charley?), so a hurricane warning has been issued for the entire
coastline from Florida City (south of Miami) to Flagler Beach (near
Daytona Beach). Even if the forecast is dead on, a large section of the
warning area will likely see hurricane force winds because of the size
of the storm. Any significant deviation in the track could still bring
the area of hurricane force winds further north or south, but that looks
unlikely at this point. It is very important for everyone in the warning
area to heed the directions of local emergency officials. People that
live in low-lying areas or mobile homes should NOT stay in their homes.
About 1.2 million people fit in this category and have been told to
evacuate to safer locations. Also, remember that the high winds of a
hurricane can extend well inland past the coast. Hurricane force winds
can be felt as far inland as 150 miles or more in a strong, fast moving
storm -- as Charley showed in the Orlando area. Frances is forecast to
turn northwestward over Florida and weaken to tropical storm force about
half a day after landfall. If it stays further west, it could cross
Florida and restregthen in the Gulf of Mexico before a second landfall
in the Florida Panhandle. Thus, residents as far west as Mobile, Alabama
should keep an eye on this storm over the weekend. 

At 21Z, Frances was located about 375 miles east-southeast of the lower
Florida East Coast, at 24.1N  74.8W, moving towards the northwest near 9
kt. Maximum sustained winds were at 120 kt and the minimum central
pressure was 946 mb. 

Please visit my tropical Atlantic headquarters.

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