04 September 2004

Frances crawls ashore east Florida coast, Ivan strengthens...

From Jonathan Vigh: 
Yesterday, Hurricane Frances was lashing Grand Bahama Island on her way
towards Florida. Today, she was still crossing that island! A C-MAN station
on the west part of the island was in the eye for approximately 10 hours
today. The eastern part of the eyewall has finally crossed over that end of
the island and the wind has picked back up to gusts of 80 kts. Currently,
Frances is coming ashore between West Palm Beach and Fort Pierce. Her exact
point of landfall doesn't matter very much because her eye is 70 miles
across! Yesterday's episode of vertical wind shear and dry air disrupted her
core long enough to let the wind field spread out. Storms often have trouble
regrouping once they have a broad wind field because it is hard to spin up
the central part of the storm. The shear appears to have let up somewhat
today, and deep thunderstorms have wrapped all the way around the center of
Frances, forming a very large eye. Within the eye, a weak circulation
appears to be trying to organize as well, but it is doubtful that this will
have much of an effect before landfall. One mechanism which could possibly
help tighten up the core of Frances (leading to intensification) is the
friction with the Florida coast. As the eyewall has been starting to move
onshore this evening, the eye deformed a bit, becoming elliptical for a
while. The greater friction over land may have helped contract the eye by be
helping to squash the eye in the east-west direction, which may help it
contract. On her current pace, the eye of Frances should be completely
onshore in 5-12 hours. This will bring a halt to any possible
intensification -- for a little while. If the eye remains at the current
size, when the eastern end finally moves onshore, the western end will be
most of the way to the other side of Florida!  

Sometime tomorrow morning, Frances should start moving at a more respectable
pace as a trough weakens the ridge that has been blocking her path. She is
likely to finish crosssing Florida by tomorrow night and reemerge out into
the Gulf of Mexico as a tropical storm (this means that most of Florida's
west coast will get tropical storm conditions, including Tampa which was
missed by Charley three weeks ago). Some restregthening is possible, and
then Frances will likely make her 2nd (and final) landfall in the Florida
Panhandle. By the time this event is over, nearly all of Florida will likely
have experienced at least tropical storm force winds and large amounts of

Many of the reporting stations in the immediate vicinity of landfall have
stopped reporting, likely due to power outages. Most of the wind reports
thusfar have been fairly consistent with a category 1 hurricane, but there
have been very few reports since the eyewall actually started moving onshore
a few hours ago. Up till this afternoon, the highest wind report was 91 mph
at Juper River Inlet and 90 mph near West Palm Beach. The outer rainbands
have also packed a punch, causing scattered damage and some power outages as
far south as Miami, as far west as Tampa, and as far north as Orlando and
Daytona Beach. At least 1.1 million customers are now without power and this
number will rapidly grow as the night goes on. 

At 03Z, Frances was at 27.1N  79.7W, moving west-northwest at 5 kt with
maximum susatined winds at 90 kt, and a minimum central pressure of 960 mb. 

Frances will still be with us for several more days, but five days from now,
Ivan may take the spotlight. The storm strenthened today, looking better and
better in the satellite imagery. Ivan is nearly to hurricane stength, and
with low shear and warm waters for at least the next 3 days, there is not
much to keep the storm from steadily strengthening. The forecast calls for
Ivan to cross the central Windward Islands in a little over 3 days, possibly
hitting Hispanola at 5 days as a major hurricane. It is still too soon to
say, but Ivan may pose an additional threat to storm-weary Florida in a
little over a week from now. 

At 03Z, Ivan was at 9.4N  42.4W, moving westward at 16 kt, with estimated
maximum sustained winds at 60 kt and a minimum central pressure of 991 mb.

For other information including preliminary wind and damage reports, see

Please visit my tropical Atlantic headquarters.

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