[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 230847
TCDAT1
HURRICANE JEANNE DISCUSSION NUMBER  39
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT THU SEP 23 2004

INFRARED IMAGERY SINCE THE SATELLITE ECLIPSE PERIOD SHOW THAT CLOUD
TOPS HAVE COOLED AROUND THE EYE OF JEANNE...BUT THAT THE EYE HAS
BECOME MORE CLOUD FILLED.  SATELLITE INTENSITY ESTIMATES REMAIN 90
KT FROM ALL AGENCIES...SO THE INITIAL INTENSITY WILL REMAIN 85 KT.
CIRRUS OUTFLOW IS CURRENTLY GOOD IN THE NORTHWESTERN QUADRANT AND
FAIR TO POOR ELSEWHERE.

POST-ECLIPSE IMAGES SHOW THAT JEANNE HAS MOVED VERY LITTLE SINCE
0315Z...PERHAPS JUST A LITTLE WESTWARD.  THE INITIAL MOTION IS A
SOMEWHAT UNCERTAIN 260/3.  A DEEP-LAYER ANTICYCLONE OVER THE EASTERN
UNITED STATES IS MOVING EASTWARD OR BUILDING INTO THE ATLANTIC...AND
LARGE SCALE MODELS FORECAST THIS TO CONTINUE THROUGH 72 HR.  THIS
SHOULD MOVE JEANNE IN A GENERAL WESTERLY DIRECTION WITH
ACCELERATION.  AFTER 72 HR...JEANNE BECOMES LOCATED SOUTHWEST OF
THE ANTICYCLONE...WHICH BEGINS TO ELONGATE NORTH-SOUTH.  THIS WOULD
ALLOW A NORTHWARD TURN AND EVENTUAL RECURVATURE INTO THE WESTERLIES.
AS IS OFTEN THE CASE...THE QUESTION IS WHERE WILL THE TURN OCCUR.
THE NOGAPS AND THE UKMET FORECAST THE TURN TO OCCUR AFTER JEANNE
HAS HIT SOUTHEASTERN FLORIDA.  THE GFS...GFDL... AND CANADIAN
FORECAST AN EARLIER TURN...WHICH WOULD BRING JEANNE NEAR OR OVER
EAST CENTRAL OR NORTHEASTERN FLORIDA.  THE DIFFERENCE IN THE MODELS
SEEMS TO BE THE FORWARD SPEED...WITH THE FASTER UKMET AND NOGAPS
REACHING SOUTHEASTERN FLORIDA...WHILE THE OTHER MODELS HAVE A
SLOWER WESTWARD MOTION AND DO NOT BRING JEANNE AS FAR WEST BEFORE
THE TURN.  WHILE THE NOGAPS SOLUTION CANNOT BE RULED OUT...THE
UKMET HAS JEANNE AT 70.8W AT 1200Z THIS MORNING AND THUS APPEARS
TOO FAST.  THE FORECAST TRACK IS SHIFTED WESTWARD FROM THE PREVIOUS
TRACK AND NOW CALLS FOR LANDFALL IN EAST CENTRAL FLORIDA.  IT IS
ALONG THE LINE OF THE MODEL CONSENSUS BUT A LITTLE SLOWER.

THE INTENSITY FORECAST REMAINS TRICKY.  JEANNE IS CURRENTLY OVER SEA
SURFACE TEMPERATURES OF ABOUT 27C...LIKELY BROUGHT ABOUT BY
UPWELLING CAUSED BY THE SLOW-MOVING HURRICANE.  SINCE JEANNE
REMAINS SLOW MOVING...THIS SUGGESTS THAT THE CURRENT INCREASE IN
CONVECTIVE ORGANIZATION MAY BE TEMPORARY.  ONLY SLOW STRENGTHENING
IS LIKELY WHILE JEANNE REMAINS EAST OF 72W.  THE WATERS ARE ABOUT
28C WEST OF 72W...AND WHEN JEANNE REACHES THEM IT SHOULD BE IN A
RATHER FAVORABLE UPPER-LEVEL WIND PATTERN.  THUS...THE INTENSITY
FORECAST SHOWS STRENGTHENING.  INTENSITY GUIDANCE IS STILL
RELUCTANT TO FORECAST JEANNE MUCH ABOVE 95-100 KT...AND THE
INTENSITY FORECAST WILL SHOW 95 KT IN AGREEMENT WITH THIS.
HOWEVER...IT WOULD BE NO SURPRISE TO SEE JEANNE REACH MAJOR
HURRICANE STATUS IN 48-72 HR.  AFTER 72 HR...LAND INTERACTION AND
INCREASING SHEAR SHOULD PRODUCE SIGNIFICANT WEAKENING.

GIVEN THE FORECAST OF THE STEERING CURRENTS...FLORIDA SHOULD PAY
CLOSE ATTENTION TO THE EVOLUTION OF JEANNE.

FORECASTER BEVEN

FORECAST POSITIONS AND MAX WINDS

INITIAL      23/0900Z 25.5N  69.5W    85 KT
 12HR VT     23/1800Z 25.4N  70.5W    85 KT
 24HR VT     24/0600Z 25.4N  72.1W    90 KT
 36HR VT     24/1800Z 25.6N  74.0W    90 KT
 48HR VT     25/0600Z 26.0N  75.9W    95 KT
 72HR VT     26/0600Z 27.0N  79.5W    95 KT
 96HR VT     27/0600Z 29.5N  81.5W    85 KT...INLAND
120HR VT     28/0600Z 34.0N  80.0W    75 KT...INLAND


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