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Tropical Storm LESLIE (Text)

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TROPICAL STORM LESLIE DISCUSSION NUMBER  13
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
1100 AM AST SUN SEP 02 2012
 
LESLIE REMAINS A SHEARED TROPICAL CYCLONE.  THE LOW-LEVEL CENTER
BECAME WELL-SEPARATED FROM THE MAIN AREA OF SHOWERS AND
THUNDERSTORMS EARLY THIS MORNING...BUT WITHIN THE PAST HOUR OR TWO
A NEW BURST OF CONVECTION HAS DEVELOPED A LITTLE CLOSER TO THE
CENTER.  EARLIER ASCAT DATA INDICATED THAT THE AREA OF STRONGEST
WINDS WAS LOCATED WELL EAST OF THE CENTER AND THEY HAVE LIKELY
PASSED VERY CLOSE TO NOAA BUOY 41044 THIS MORNING.  THE BUOY HAS
REPORTED PEAK 1-MINUTE WINDS OF 43-47 KT DURING THE PAST SEVERAL
HOURS.  HOWEVER...SINCE STRONGER WINDS MAY BE OCCURRING IN THE
CONVECTION...THE INITIAL WIND SPEED IS SET AT 55 KT.
 
NORTHWESTERLY SHEAR IS EXPECTED TO CONTINUE PLAGUING LESLIE
DURING THE NEXT SEVERAL DAYS.  IN FACT...IT IS FORECAST TO BECOME
STRONGER BETWEEN 24 AND 60 HOURS...WHICH SHOULD CAUSE LESLIE TO
WEAKEN A LITTLE. DURING THIS TIME...THE NHC FORECAST FOLLOWS THE
LGEM GUIDANCE...WHICH TYPICALLY HANDLES THE INTENSITY OF TROPICAL
CYCLONES BETTER IN EVOLVING SHEAR CONDITIONS.  AT DAYS 4 AND
5...THE SHEAR IS FORECAST TO RELAX AND LESLIE IS EXPECTED TO BE IN
A MORE FAVORABLE ENVIRONMENT FOR STRENGTHENING.  AS A RESULT...THE
NHC FORECAST CALLS FOR INTENSIFICATION LATE IN THE FORECAST PERIOD.
 
VISIBLE SATELLITE IMAGERY SHOWS THAT LESLIE WAS LOCATED A LITTLE
WEST OF THE PREVIOUS TRACK AND THAT IT HAS SLOWED DOWN DURING THE
PAST COUPLE OF HOURS.  HOWEVER...THE LONGER TERM MOTION ESTIMATE IS
NORTHWESTWARD OR 305 DEGREES AT 13 KT. THE TRACK GUIDANCE IS IN
GOOD AGREEMENT ON MOVING LESLIE NORTHWESTWARD...THEN TURNING IT
NORTHWARD IN 24-36 HOURS AS IT MOVES TOWARD A BREAK IN THE
SUBTROPICAL RIDGE.  AFTER THAT TIME...A MID-LATITUDE TROUGH IS
FORECAST TO BY-PASS LESLIE WHILE A MID-LEVEL RIDGE BUILDS OVER THE
WESTERN ATLANTIC.  THIS SHOULD CAUSE LESLIE TO MOVE VERY SLOWLY
NORTHWARD DURING THE REMAINDER OF THE FORECAST PERIOD.  THE NHC
TRACK HAS BEEN SHIFTED A LITTLE WESTWARD...PARTIALLY DUE TO THE
MORE WESTWARD INITIAL POSITION.  THE NEW TRACK IS NEAR THE MIDDLE
OF THE GUIDANCE ENVELOPE AND BETWEEN THE ECMWF AND GFS MODELS.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  02/1500Z 21.3N  61.1W   55 KT  65 MPH
 12H  03/0000Z 23.0N  62.5W   55 KT  65 MPH
 24H  03/1200Z 24.5N  63.4W   50 KT  60 MPH
 36H  04/0000Z 25.5N  63.6W   50 KT  60 MPH
 48H  04/1200Z 26.2N  63.6W   50 KT  60 MPH
 72H  05/1200Z 27.3N  63.5W   50 KT  60 MPH
 96H  06/1200Z 28.3N  63.5W   55 KT  65 MPH
120H  07/1200Z 29.5N  64.0W   65 KT  75 MPH
 
$$
FORECASTER BROWN
 
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