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TROPICAL STORM DEAN DISCUSSION NUMBER   2
NATIONAL WEATHER SERVICE MIAMI FL
5 PM EDT WED AUG 22 2001
 
THE LATEST REPORTS FROM THE HURRICANE HUNTER AIRCRAFT MONITORING
DEAN INDICATE A SMALL CENTER WITH A CENTRAL PRESSURE OF 1009 MB AND
FLIGHT LEVEL WINDS OF 63 KT.  THE CENTER IS EXPOSED AT THE NORTHERN
END OF A CONVECTIVE BAND THAT TRAILS SOUTHWARD ACROSS THE VIRGIN
ISLANDS.  THE MAXIMUM WINDS REMAIN AT 50 KT ON THIS ADVISORY.

THE INITIAL MOTION IS 295/20.  THERE IS NO CHANGE IN THE TRACK
FORECAST PHILOSOPHY FROM THE PREVIOUS PACKAGE.  DEAN IS BEING
STEERED BY THE BERMUDA HIGH TO THE NORTHEAST...AND IN THE SHORT
TERM SHOULD CONTINUE THE PRESENT WEST-NORTHWESTWARD MOTION.  LATER
IN THE FORECAST PERIOD THE STORM SHOULD APPROACH A LARGE DEEP-LAYER
TROUGH LOCATED OFF THE U.S. EAST COAST...WHICH SHOULD SLOW DEAN
AND RECURVE IT NORTHEASTWARD.  NHC HURRICANE GUIDANCE AGREES WITH
THIS SCENARIO...AS DOES THE OFFICIAL FORECAST.  SHOULD THIS FORECAST
VERIFY...DEAN WOULD NOT BE A THREAT TO THE MAINLAND UNITED STATES.
 
WHILE DEAN IS CURRENTLY UNDER SOME WESTERLY SHEAR CAUSED MAINLY
BY STRONG LOW-LEVEL FLOW...SATELLITE IMAGERY INDICATES SOME STRONG
NORTHERLY FLOW MAY SOON IMPACT THE STORM IN RESPONSE TO AN UPPER
LEVEL RIDGE BUILDING AHEAD OF IT.  SHOULD THE SMALL AND LIKELY
FRAGILE CIRCULATION SURVIVE THE NEXT 12 OR 24 HR...IT WOULD MOVE
UNDER THIS RIDGE AND LIKELY INTENSIFY.  THE INTENSITY FORECAST
REFLECTS THIS PHILOSOPHY.  IT IS NOTABLE THAT THE SHIPS MODEL
MAKES DEAN A HURRICANE IN 12 HR AND STRENGTHENS IT TO 90 KT BY
72 HR.
 
THE FORECAST TRACK AND WIND RADII REQUIRE WATCHES AND WARNINGS FOR
PORTIONS OF THE BAHAMAS.
 
FORECASTER BEVEN
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     22/2100Z 19.5N  66.7W    50 KTS
12HR VT     23/0600Z 20.8N  69.3W    50 KTS
24HR VT     23/1800Z 22.4N  71.4W    55 KTS
36HR VT     24/0600Z 24.2N  72.4W    60 KTS
48HR VT     24/1800Z 25.5N  72.0W    65 KTS
72HR VT     25/1800Z 27.5N  71.0W    70 KTS
 
 
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