[Tropical] Tropical Cyclone Discussion

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WTNT41 KNHC 231459
TCDAT1
HURRICANE JEANNE DISCUSSION NUMBER  40
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
11 AM EDT THU SEP 23 2004

SATELLITE IMAGERY EARLIER THIS MORNING INDICATED A WELL-DEFINED
CLOUD-FREE EYE WITH A RING OF COLD TOPS SURROUNDING THE EYE. THE
DVORAK INTENSITY ESTIMATE WAS A CONSENSUS T5.5...OR 102 KT...FROM
ALL THREE SATELLITE AGENCIES. HOWEVER...DURING THE PAST COUPLE OF
HOURS...CLOUD TOPS HAVE SIGNIFICANTLY WARMED AND THE EYE HAS BECOME
A LITTLE MORE RAGGED. AS SUCH...THE INTENSITY IS ONLY BEING
INCREASED TO 90 KT FOR THIS ADVISORY.

THE INITIAL MOTION IS A SOMEWHAT UNCERTAIN 270/4. JEANNE IS
SURROUNDED BY HIGH PRESSURE EVERYWHERE BUT THE SOUTH...SO THERE HAS
BEEN LITTLE IN THE WAY OF DEFINITIVE MOVEMENT THE PAST 6 HOURS.
HOWEVER...ALL OF THE AVAILABLE NHC MODEL GUIDANCE INDICATES THE
PRESSURES TO THE WEST OF JEANNE SHOULD BEGIN TO DECREASE AS IVAN
MOVES NORTHWESTWARD AND THAT SHOULD ALLOW FOR A SLOW WESTWARD
MOTION TO BEGIN SHORTLY. IN THE LONGER TERM...THE TROUGH-RIDGE
PATTERN OVER THE CENTRAL AND EASTERN U.S. AND INTO THE CENTRAL
ATLANTIC IS FORECAST TO AMPLIFY BY ALL OF THE GLOBAL MODELS. THIS
RESULTS IN A RIDGE BETWEEN BERMUDA AND THE U.S. MID-ATLANTIC COAST
TO REMAIN NEARLY STATIONARY THE NEXT 48-72 HOURS WHILE BUILDING
SLOWLY SOUTHWARD. A DEEP-LAYER EASTERLY FLOW REGIME IS EXPECTED TO
MOVE JEANNE WESTWARD FOR THE NEXT 48-60 HOURS...WITH A POSSIBLE
TURN TO THE NORTHWEST AS THE HURRICANE NEARS THE FLORIDA EAST COAST
IN ABOUT 72 HOURS. THE OFFICIAL TRACK WAS NUDGED WESTWARD OUT OF
RESPECT FOR THE NOGAPS AND GFDN MODELS...WHICH WERE FIRST TWO
MODELS AND THE MOST CONSISTENT ONES TO INDICATE A WESTWARD MOTION
TOWARD FLORIDA.

THE INTENSITY FORECAST IS STILL TRICKY. OCEAN CONDITIONS NEAR JEANNE
ARE CURRENTLY NOT FAVORABLE FOR SIGNIFICANT STRENGTHENING TO OCCUR.
HOWEVER...BY 24-48 HOURS...THE OUTFLOW PATTERN IS EXPECTED TO
IMPROVE AND JEANNE IS FORECAST TO MOVE OVER WARMER WATER NEAR THE
BAHAMAS. THIS SHOULD ALLOW FOR SOME ADDITIONAL STRENGTHENING TO
OCCUR. BY 72 HOURS...JUST PRIOR TO LANDFALL...INCREASING SOUTH TO
SOUTHWESTERLY UPPER-LEVEL SHEAR MAY BRING ABOUT SOME SIGNIFICANT
WEAKENING...BUT THIS IS TOO CLOSE TO CALL RIGHT NOW.

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

FORECASTER STEWART

FORECAST POSITIONS AND MAX WINDS

INITIAL      23/1500Z 25.6N  69.7W    90 KT
 12HR VT     24/0000Z 25.6N  70.9W    90 KT
 24HR VT     24/1200Z 25.6N  72.6W    95 KT
 36HR VT     25/0000Z 25.7N  74.6W   100 KT
 48HR VT     25/1200Z 26.0N  76.8W   100 KT
 72HR VT     26/1200Z 27.3N  80.2W    95 KT...NR FLORIDA EAST COAST
 96HR VT     27/1200Z 30.5N  81.5W    65 KT...INLAND
120HR VT     28/1200Z 35.0N  78.5W    45 KT...INLAND


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