Hurricane ALEX
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HURRICANE ALEX DISCUSSION NUMBER 20
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
5 AM EDT THU AUG 05 2004
ALEX REMAINS WELL ORGANIZED THIS MORNING...WITH A WELL-DEFINED EYE
SURROUNDED BY CONVECTIVE TOPS OF -65C TO -75C. INDEED...THE CLOUD
TOPS HAVE COOLED SOMEWHAT OVER THE PAST FEW HOURS. SATELLITE
INTENSITY ESTIMATES ARE 102 KT FROM ALL AGENCIES. BASED ON
THIS...THE MAXIMUM WINDS REMAIN 105 KT. THE UPPER-LEVEL OUTFLOW IS
FAIR IN THE NORTHEASTERN SEMICIRCLE AND POOR ELSEWHERE.
THE INITIAL MOTION IS NOW 065/25. ALEX IS WELL EMBEDDED IN THE
WESTERLIES AND SHOULD CONTINUE AN ACCELERATING EAST-NORTHEASTWARD
MOTION FOR 24 HR OR SO...FOLLOWED BY A GRADUAL TURN TOWARD THE
EAST. ALL TRACK GUIDANCE AGREES WITH THIS SCENARIO OUT TO 48-72
HR...AND THE OFFICIAL FORECAST IS AN UPDATE OF THE PREVIOUS
PACKAGE.
THE CLOUD TOP COOLING CURRENTLY OCCURRING IS LIKELY TO BE THE LAST
GASP FOR ALEX. THE HURRICANE SHOULD MOVE NORTH OF THE GULF STREAM
INTO MUCH COLDER SEA SURFACE TEMPERATURES DURING THE NEXT 12-18
HOURS WHICH SHOULD CAUSE SIGNIFICANT WEAKENING. ALEX WILL BEGIN
EXTRATROPICAL TRANSITION AFTER 24 HR AND COMPLETE IT BY 48 HR.
WHILE DETAILS DIFFER...ALL LARGE-SCALE MODELS AGREE THAT
EXTRATROPICAL ALEX WILL MERGE WITH EITHER ANOTHER EXTRATROPICAL LOW
OR A COLD FRONT BY 72 HR AND LOSE ITS IDENTITY...AND THE INTENSITY
FORECAST FOLLOWS THIS SCENARIO.
FORECASTER BEVEN
FORECAST POSITIONS AND MAX WINDS
INITIAL 05/0900Z 40.0N 61.5W 105 KT
12HR VT 05/1800Z 42.0N 56.2W 95 KT
24HR VT 06/0600Z 45.0N 46.5W 75 KT
36HR VT 06/1800Z 47.0N 36.5W 60 KT...BECOMING EXTRATROPICAL
48HR VT 07/0600Z 47.0N 26.5W 55 KT...EXTRATROPICAL
72HR VT 08/0600Z...ABSORBED BY EXTRATROPICAL LOW
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