Hurricane LESLIE

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HURRICANE LESLIE DISCUSSION NUMBER  30
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
500 PM AST THU SEP 06 2012
 
THERE HAS NOT BEEN A SIGNIFICANT CHANGE IN THE SATELLITE
PRESENTATION DURING THE DAY WITH THE EXCEPTION THAT THE OVERALL
CLOUD PATTERN IS A LITTLE SMALLER. THERE IS A CONVECTIVE BAND
WRAPPING AROUND A SMALL CENTRAL DENSE OVERCAST...WHICH GIVES THE
APPEARANCE OF BETTER ORGANIZATION. HOWEVER...MICROWAVE DATA DOES NOT
SHOW A WELL-DEFINED INNER CORE AT THIS TIME. DVORAK T-NUMBERS FROM
BOTH TAFB AND SAB SUPPORT KEEPING AN INITIAL INTENSITY OF 65 KNOTS.
SINCE LESLIE HAS BEEN MOVING LITTLE...IT IS PRODUCING UPWELLING
RESULTING IN LOWER SEA SURFACE TEMPERATURES IN THE AREA. THE
UPWELLING IN COMBINATION WITH THE SHEAR WOULD NOT FAVOR ANY
SIGNIFICANT STRENGTHENING UNTIL LESLIE BEGINS TO MOVE NORTHWARD OVER
UNDISTURBED WARMER WATERS IN A DAY OR TWO. THE NHC FORECAST CALLS
FOR A MODEST STRENGTHENING BEGINNING IN 24 HOURS.
 
LESLIE CONTINUES TO BE EMBEDDED WITHIN VERY LIGHT STEERING
CURRENTS...AND CONSEQUENTLY IT HAS REMAINED PRACTICALLY STATIONARY
ALL DAY. THERE ARE NO INDICATIONS FROM GLOBAL MODELS OR OTHER
GUIDANCE THAT LESLIE WILL BEGIN TO MOVE FASTER ANY TIME SOON. IN
FACT...THE NHC FORECAST MOVES LESLIE NORTHWARD ONLY 120 NAUTICAL
MILES IN TWO DAYS.  BEYOND 48 HOURS...THE SUBTROPICAL RIDGE IS
FORECAST TO BUILD TO THE EAST OF LESLIE...AND THIS FEATURE IN
COMBINATION WITH AN APPROACHING MID-LEVEL TROUGH WILL FORCE THE
HURRICANE ON A NORTHWARD TRACK...AND THEN NORTHEASTWARD WITH A
GRADUAL INCREASE IN FORWARD SPEED. THE NHC FORECAST CONTINUES TO BE
VERY CLOSE TO THE CONSENSUS AND BETWEEN THE GFS AND THE ECMWF
GLOBAL MODELS. IT IS INTERESTING TO NOTE THAT THE WHOLE GUIDANCE
ENVELOPE SHIFTED A LITTLE BIT EASTWARD AWAY FROM BERMUDA THIS
AFTERNOON...BUT THE NHC FORECAST PREFERS TO MAKE THAT EASTWARD
ADJUSTMENT MORE GRADUALLY.
 
THE WIND FIELD OF LESLIE...COMBINED WITH ITS EXPECTED SLOW MOTION...
WILL GENERATE LONG-PERIOD SWELLS THAT WILL PRODUCE LARGE WAVES AND
LIFE-THREATENING RIP CURRENTS ON BERMUDA AND ALONG MUCH OF THE U.S.
EAST COAST FOR THE REMAINDER OF THIS WEEK.
 

FORECAST POSITIONS AND MAX WINDS
 
INIT  06/2100Z 26.5N  62.2W   65 KT  75 MPH
 12H  07/0600Z 26.6N  62.2W   65 KT  75 MPH
 24H  07/1800Z 27.0N  62.4W   70 KT  80 MPH
 36H  08/0600Z 27.5N  62.5W   75 KT  85 MPH
 48H  08/1800Z 28.5N  62.6W   85 KT 100 MPH
 72H  09/1800Z 32.0N  62.2W   90 KT 105 MPH
 96H  10/1800Z 35.5N  60.0W   80 KT  90 MPH
120H  11/1800Z 41.5N  56.0W   70 KT  80 MPH
 
$$
FORECASTER AVILA
 
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