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Tropical Storm LESLIE


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TROPICAL STORM LESLIE DISCUSSION NUMBER  38
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
500 PM AST SAT SEP 08 2012
 
VISIBLE SATELLITE IMAGES REVEAL THAT THE CLOUD PATTERN HAS BECOME
SYMMETRIC AROUND A LARGE CLOUDLESS CENTER OF CIRCULATION...
COMMONLY REFERRED TO AS A TRUCK TIRE/DOUGHNUT-TYPE PATTERN. SINCE
THE CONVECTION IS NOT VERY DEEP AND DVORAK T-NUMBERS HAVE NOT
INCREASED YET...THE INITIAL INTENSITY IS KEPT AT 55 KNOTS.
GIVEN THAT THE UPPER-LEVEL OUTFLOW IS PERFECTLY ESTABLISHED IN ALL
QUADRANTS...AND THAT LESLIE IS BEGINNING TO MOVE OVER WARM
WATERS...THE NHC FORECAST CALLS FOR LESLIE TO REGAIN HURRICANE
STATUS IN A DAY OR SO.  EXTRATROPICAL TRANSITION SHOULD OCCUR BY
DAY 4 WHEN LESLIE IS NEAR NEWFOUNDLAND.

LESLIE IS MOVING TOWARD THE NORTH AT ABOUT 7 KNOTS. A LARGE
MID-LEVEL TROUGH IS RAPIDLY AMPLIFYING OVER THE EASTERN UNITED
STATES...AND THIS PATTERN WILL FORCE LESLIE TO RECURVE AND INCREASE
IN FORWARD SPEED.  TRACK GUIDANCE CONTINUES TO BE IN VERY GOOD
AGREEMENT IN THE NEXT 3 DAYS...BUT DIFFERS SIGNIFICANTLY IN SPEED
BY 96 HOURS WHEN LESLIE IS ABOUT TO LOSE TROPICAL CHARACTERISTICS.
THE OFFICIAL FORECAST FOLLOWS THE CONSENSUS DURING THE FIRST THREE
DAYS...AND THEN LEANS TOWARD THE GFS AND OCEAN PREDICTION CENTER
GUIDANCE.
 
THE WIND FIELD OF LESLIE...COMBINED WITH ITS EXPECTED SLOW MOTION...
WILL CONTINUE TO 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 THROUGH THE WEEKEND AND INTO EARLY NEXT
WEEK.
 
  
FORECAST POSITIONS AND MAX WINDS
 
INIT  08/2100Z 29.4N  62.5W   55 KT  65 MPH
 12H  09/0600Z 30.4N  62.3W   60 KT  70 MPH
 24H  09/1800Z 32.2N  62.0W   65 KT  75 MPH
 36H  10/0600Z 34.0N  61.5W   75 KT  85 MPH
 48H  10/1800Z 36.0N  60.5W   80 KT  90 MPH
 72H  11/1800Z 44.0N  56.5W   70 KT  80 MPH
 96H  12/1800Z 46.0N  52.0W   60 KT  70 MPH...POST-TROP/EXTRATROP
120H  13/1800Z 48.0N  46.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER AVILA
 
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