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TROPICAL STORM LESLIE DISCUSSION NUMBER   6
NATIONAL WEATHER SERVICE MIAMI FL
11 PM EDT THU OCT 05 2000
 
LESLIE HAS CHANGED LITTLE IN STRUCTURE OVER THE PAST FEW HOURS...
WITH A MOSTLY EXPOSED LOW-LEVEL CENTER AND DISORGANIZED CONVECTION
OVER THE EAST QUADRANT.  THE NOAA HURRICANE HUNTER FOUND A CENTRAL
PRESSURE OF 1009-1010 MB AND MAXIMUM FLIGHT LEVEL WINDS OF 37 KT...
WHICH WOULD NOT REALLY SUPPORT KEEPING LESLIE A STORM.  HOWEVER...
SHIP 8PNK REPORTED 36 KT WINDS IN ONE OF THE CONVECTIVE CLUSTERS AT
00Z.  THE MAXIMUM WINDS ARE THUS KEPT AT 35 KT.  AN AIR FORCE
RESERVE HURRICANE HUNTER WILL INVESTIGATE THE STORM AROUND 06Z.

THE INITIAL MOTION IS 085/11.  LESLIE IS EMBEDDED IN A GENERAL WEST
TO WEST-SOUTHWEST MID/UPPER LEVEL FLOW...WHICH IS PUSHING THE STORM
INTO THE BERMUDA-AZORES HIGH AT LOW LEVELS.  THE OVERALL STEERING
FLOW SHOULD INCREASE AND BECOME SOUTHWESTERLY AS A LARGE DEEP-LAYER
TROUGH DEVELOPS OVER THE EASTERN UNITED STATES.  THIS SHOULD
ACCELERATE LESLIE TO THE NORTHEAST.  ALL TRACK GUIDANCE AGREES ON
THIS...WITH THE ONLY DIFFERENCES BEING IN HOW FAST LESLIE WILL MOVE. 
THE OFFICIAL FORECAST WILL LEAN TOWARD THE FASTER GFDL...GFDN...
AVN...AND UKMET...ALTHOUGH IT WILL BE A LITTLE SLOWER THAN THOSE
MODELS.

THE INTENSITY FORECAST IS SOMEWHAT TRICKY.  WESTERLY SHEAR APPEARS
TO BE INCREASING...AND UPPER LEVEL WINDS FORECAST BY THE LARGE SCALE
MODELS DO NOT APPEAR FAVORABLE FOR STRENGTHENING. INDEED...MOST
INTENSITY GUIDANCE FORECAST EITHER WEAKENING OR NO CHANGE IN
STRENGTH.  ON THE OTHER HAND...LESLIE HAS A LARGE ENVELOPE...AND
ACCELERATION WOULD INCREASE THE WINDS ON THE RIGHT SIDE OF THE
CIRCULATION.  THERE COULD ALSO BE A DECREASE IN STORM-RELATIVE
SHEAR...WHICH COULD LEAD TO SOME STRENGTHENING SIMILAR TO THAT OF
FLORENCE A FEW WEEKS AGO.  BAROCLINICALLY-INDUCED STRENGTHENING IS
ALSO POSSIBLE BEFORE EXTRATROPICAL TRANSITION. THE INTENSITY
FORECAST WILL CONTINUE TO CALL FOR SOME GRADUAL STRENGTHENING...BUT
NOT TO THE LEVEL OF THE GFDN WHICH HAS LESLIE AT 70 KT IN 36 HR. 
HOWEVER...IT IS ALSO POSSIBLE THAT LESLIE COULD WEAKEN TO A
DEPRESSION BEFORE PASSING BERMUDA.
 
WITH THE CLOSEST APPROACH TO BERMUDA NOW FORECAST TO BE IN 36 HR...A
TROPICAL STORM WATCH HAS BEEN ISSUED FOR THE ISLAND.
 
FORECASTER BEVEN
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL     06/0300Z 30.6N  73.8W    35 KTS
12HR VT     06/1200Z 30.8N  71.7W    35 KTS
24HR VT     07/0000Z 31.7N  69.1W    40 KTS
36HR VT     07/1200Z 33.5N  66.2W    40 KTS
48HR VT     08/0000Z 36.5N  62.5W    45 KTS
72HR VT     09/0000Z 45.5N  53.0W    45 KTS...EXTRATROPICAL
 
 
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