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HURRICANE MICHELLE DISCUSSION NUMBER 27
NATIONAL WEATHER SERVICE MIAMI FL
4 AM EST MON NOV 05 2001
THE LAST REPORT FROM A NOAA AIRCRAFT...ALONG WITH RADAR AND
SATELLITE OBSERVATIONS...INDICATE THAT MICHELLE IS CONTINUING TO
WEAKEN WHILE ACCELERATING NORTHEASTWARD. UPPER-LEVEL OUTFLOW IS
CONFINED MAINLY TO THE NORTHERN SEMICIRCLE DUE TO SOUTHWESTERLY
UPPER-LEVEL SHEAR IMPINGING ON THE SYSTEM.
THE INITIAL MOTION ESTIMATE IS 050/15. THERE IS NO SIGNIFICNAT
CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. ALL OF THE
GLOBAL MODELS...EXCEPT FOR THE AVN MODEL...AND MOST OF THE NHC
FORECAST GUIDANCE AGREE ON MICHELLE CONTINUING TO ACCELERATE
NORTHEASTWARD ACROSS THE NORTHERN AND CENTRAL BAHAMAS TOWARD
BERMUDA. WATER VAPOR IMAGERY INDICATES THE MID- TO UPPER-LEVEL
TROUGH OVER THE EASTERN U.S. AND THE GULF OF MEXICO HAS CONTINUED TO
DIG SOUTHWARD WHILE SHIFTLY STEADILY EASTWARD. THIS FLOW PATTERN
SHOULD CAUSE MICHELLE TO GRADUALLY LIFT OUT TO THE NORTHEAST AND
WEAKEN DUE TO INCREASING SOUTHWESTERLY SHEAR. THE OFFICIAL FORECAST
IS CLOSE TO THE PREVIOUS FORECAST TRACK AND THE UKMET-GFDL-NOGAPS
CONSENSUS. THE AVN MODEL...WHICH HAS DONE AN OUTSTANDING JOB WITH
MICHELLE THUS FAR...APPEARS TO WEAKEN AND SPLIT THE SYSTEM INTO TWO
SEPARATE ENTITIES AND TAKES THE CYCLONE DUE EAST AFTER PASSING OVER
ANDROS ISLAND. HOWEVER...THE AVN FORECAST SEEMS UNREASONABLE AT THIS
TIME AND LESS WEIGHT WAS PLACED ON THIS SOLUTION.
CONTINUED WEAKENING IS FORECAST DUE TO INCREASING UPPER-LEVEL SHEAR.
THE GFDL ACTUALLY RE-STRENGTHENS MICHELLE TO 100 KT IN 24 HOURS...
BUT THIS SEEMS UNREASONABLE IN LIGHT OF THE STRONG VERTICAL SHEAR
ACROSS THE CYCLONE. INSTEAD...THE SHIPS INTENSITY MODEL WAS
FOLLOWED...EXCEPT THAT IT DISSIPATES THE SYSTEM IN 60 HOURS. WE
ANTICIPATE THAT EXTRATROPICAL TRANSITION WILL OCCUR INSTEAD.
FORECASTER STEWART
FORECAST POSITIONS AND MAX WINDS
INITIAL 05/0900Z 23.5N 79.4W 85 KTS
12HR VT 05/1800Z 24.9N 77.6W 80 KTS
24HR VT 06/0600Z 26.5N 74.1W 75 KTS
36HR VT 06/1800Z 28.0N 70.1W 65 KTS...BECOMING EXTRATROPICAL
48HR VT 07/0600Z 30.2N 65.4W 55 KTS...EXTRATROPICAL
72HR VT 08/0600Z 38.5N 55.0W 50 KTS...EXTRATROPICAL
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