[Tropical] Tropical Cyclone Discussion

[Nashville EMWIN]

WTNT41 KNHC 060859
TCDAT1
TROPICAL STORM FRANCES DISCUSSION NUMBER  50
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT MON SEP 06 2004

NOW THAT FRANCES HAS MOVED OVER THE WARM WATERS OF THE NORTHEAST
GULF OF MEXICO...THUNDERSTORMS ACTIVITY HAS STEADILY INCREASED NEAR
THE TIGHT CIRCULATION CENTER DURING THE PAST 6 HOURS. THE LAST
RECON REPORT AT AROUND 05Z INDICATED A RAGGED EYE WAS TRYING TO
FORM...WHICH HAS ALSO BEEN NOTED IN DOPPLER RADAR DATA FROM
TALLAHASSEE AND TAMPA. THE BANDING FEATURES TO THE NORTHWEST OF THE
CENTER OVER THE GULF OF MEXICO HAVE ALSO CONTINUED TO IMPROVE. THE
INITIAL INTENSITY OF 55 KT IS BASED ON RECON FLIGHT-LEVEL WIND
CONVERSIONS AND A DROPSONDE REPORT TO THE NORTHWEST.

THE INITIAL MOTION ESTIMATE IS 300/10 BASED ON RADAR AND RECON
OBSERVATIONS.  THE NHC MODEL GUIDANCE IN GOOD AGREEMENT ON FRANCES
MOVING WEST-NORTHWESTWARD AROUND THE SOUTHWESTERN PORTION OF THE
SUBTROPICAL RIDGE AXIS THAT EXTENDS EAST-WEST ALONG 32N LATITUDE.
THE PRIMARY DIFFERENCE IN THE MDOELS IS HOW SHARP OF A TURN FRANCES
WILL MAKE UPON REACHING 32N. THE GFS APPEARS TO MAKE TOO SHARP OF A
NORTHEASTWARD TURN GIVEN THE CURRENT LARGE DIAMETER OF FRANCES. THE
OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS FORECAST TRACK AND IS
CLOSE THE GUNA MODEL CONSENSUS.

NOW THAT THE CENTER OF FRANCES IS BACK OVER WARM WATER...SOME
RE-STRENGTHENING IS POSSIBLE. WATER TEMPERATURES ARE NEAR 83-84F
AND UPPER-LEVEL OUTFLOW IS STILL QUITE IMPRESSIVE. FRANCES COULD
REACH MINIMAL CATEGORY 1 HURRICANE STRENGTH JUST AS IT MAKES
LANDFALL IN THE CENTRAL PORTION OF THE FLORIDA PANHANDLE GIVEN THE
TIGHTER INNER-CORE CONVECTIVE BANDING FEATURES THAT HAVE DEVELOPED
AND THE RELATIVELY LOW CENTRAL PRESSURE OF 981 MB...WHICH IS
TYPICAL OF A 75-KT HURRICANE.

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL      06/0900Z 28.7N  83.5W    55 KT
 12HR VT     06/1800Z 29.9N  84.8W    65 KT...INLAND
 24HR VT     07/0600Z 31.2N  85.5W    40 KT...INLAND
 36HR VT     07/1800Z 32.4N  85.8W    30 KT...INLAND
 48HR VT     08/0600Z 33.9N  85.6W    25 KT...INLAND
 72HR VT     09/0600Z 37.8N  83.0W    20 KT...INLAND
 96HR VT     10/0600Z 42.5N  78.0W    20 KT...INLAND EXTRATROPICAL
120HR VT     11/0600Z...ABSORBED BY FRONTAL SYSTEM


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