[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT41 KNHC 050233
TCDAT1
HURRICANE FRANCES DISCUSSION NUMBER  45
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 PM EDT SAT SEP 04 2004

U.S. AIR FORCE RESERVE AND NOAA RECONNAISSANCE DATA INDICATE THAT
THE MAXIMUM SURFACE WINDS REMAIN NEAR 90 KT WITH A CENTRAL PRESSURE
OF 960 MB.  THE HURRICANE REMAINS WELL ORGANIZED ON SATELLITE AND
RADAR IMAGERY WITH AN WELL DEFINED EYEWALL ABOUT 45 N MI ACROSS.
THE SOUTHERN PORTION OF THE EYEWALL LOOKED A LITTLE RAGGED FOR A
WHILE BUT HAS RECENTLY BECOME BETTER DEFINED.  SO CONDITIONS STILL
APPEAR FAVORABLE FOR SOME STRENGTHENING DURING THE SEVERAL OR MORE
HOURS THAT THE CENTER REMAINS OVER THE WARM GULFSTREAM WATERS
BEFORE LANDFALL.

THE INITIAL MOTION ESTIMATE IS 285/04.  THE PRIMARY GLOBAL MODELS
SHOW A WEST-NORTHWESTWARD MOTION FOR 12 HOURS AT 5 TO 7 KT
WHICH SHOULD MOVE THE CENTER OF THE HURRICANE INLAND IN 12 HOURS.
THE WESTERN PORTION OF THE EYEWALL HAS ALREADY MOVED OVER THE
SOUTH-CENTRAL FLORIDA EAST COAST FROM PALM BEACH COUNTY TO MARTIN
COUNTY.  THEREAFTER THE STEERING RIDGE SURROUNDING THE HURRICANE
WHICH IS RESPONSIBLE FOR THE SLOW FORWARD SPEED WILL BE WEAKENED BY
AN APPROACHING SHORT WAVE TROUGH IN THE WESTERLIES.  ALL MODELS
SHOW A MOSTLY NORTHWESTWARD MOTION THROUGH 48 HOURS AND THEN SPREAD
OUT A LOT AFTER 48 HOURS.  THE GFDL AND NOGAPS SHOW A CONTINUED
NORTHWESTWARD MOTION AND THE GFS AND UKMET SHOW A RECURVATURE
TOWARD THE NORTHEAST.  THE OFFICIAL FORECAST IS IN THE MIDDLE OF
THE GUIDANCE FOLLOWING A CONSENSUS OF THE THESE MODELS AND IS ALSO
CLOSE TO THE FSU SUPERENSEMBLE.

THE FORECAST TRACK BRINGS THE CENTER BACK OVER THE WATERS OF THE
NORTHEASTERN GULF OF MEXICO IN 36 HOURS.  THE SLOW MOTION SHOULD
CAUSE FRANCES TO WEAKEN CONSIDERABLE OVER LAND AND IT IS NOT
EXPECTED THAT FRANCES WILL REGAIN HURRICANE INTENSITY OVER THE
GULF.

FORECASTER LAWRENCE

FORECAST POSITIONS AND MAX WINDS

INITIAL      05/0300Z 27.1N  79.7W    90 KT
 12HR VT     05/1200Z 27.3N  80.6W    80 KT...INLAND
 24HR VT     06/0000Z 28.3N  82.3W    50 KT...INLAND
 36HR VT     06/1200Z 29.5N  84.1W    60 KT...OVER WATER
 48HR VT     07/0000Z 30.7N  85.8W    50 KT...INLAND
 72HR VT     08/0000Z 33.2N  87.5W    30 KT...INLAND
 96HR VT     09/0000Z 36.0N  87.0W    25 KT...INLAND
120HR VT     10/0000Z 40.5N  84.5W    25 KT...INLAND


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