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Tropical Storm LESLIE


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TROPICAL STORM LESLIE DISCUSSION NUMBER   2
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL122012
500 PM EDT THU AUG 30 2012
 
LESLIE HAS QUICKLY ORGANIZED TODAY WITH PROMINENT BANDING FEATURES
AND INCREASED CONVECTION NEAR THE CENTER.  THE INITIAL INTENSITY IS
SET TO 40 KT AS A BLEND OF THE SUBJECTIVE AND MICROWAVE ESTIMATES.
GLOBAL MODELS ALL BUILD AN UPPER-LEVEL ANTICYCLONE NEAR THE STORM
FOR THE NEXT FEW DAYS...WHICH WOULD SEEM TO BE A FAVORABLE
ENVIRONMENT FOR FURTHER STRENGTHENING.  MOST OF THE GUIDANCE
SUGGESTS THAT LESLIE WILL BECOME A HURRICANE IN A DAY OR TWO...AND
THERE ARE EVEN A COUPLE MODELS THAT SHOW IT NEAR MAJOR HURRICANE
STRENGTH IN A FEW DAYS.  THE NHC FORECAST IS RAISED FROM THE
PREVIOUS ONE...AND IS A LITTLE BELOW THE ROBUST LGEM/SHIPS GUIDANCE
THROUGHOUT THE PERIOD.  WHILE THE TIMING IS IMPOSSIBLE TO
PINPOINT...IT WOULD NOT BE SURPRISING IF LESLIE BECAME STRONGER
THAN FORECAST IN THE THREE-TO-FIVE DAY PERIOD.  
 
THE INITIAL MOTION IS ABOUT 280/18.  LESLIE SHOULD TURN TOWARD THE
WEST-NORTHWEST IN THE NEXT 12 HOURS OR SO AS IT MOVES AROUND THE
SOUTHWESTERN SIDE OF THE SUBTROPICAL RIDGE.  A SERIES OF TROUGHS IS
EXPECTED TO DIG BETWEEN 60W-70W...WHICH SHOULD CAUSE THE STORM TO
MAKE A GRADUAL TURN TOWARD THE NORTHWEST AND NORTH IN A FEW DAYS.
MODEL GUIDANCE IS IN VERY GOOD AGREEMENT FOR THE FIRST THREE
DAYS...THEN SOME DIVERGENCE OCCURS ON WHICH TROUGH MIGHT RECURVE
THE CYCLONE.  AT THE END OF THE PERIOD...SPEED DIFFERENCES BECOME
VERY IMPORTANT ON WHETHER LESLIE MOVES QUICKLY OUT TO SEA...AS
SUGGESTED BY THE GFS...OR GETS STUCK UNDER A RIDGE...AS FORECAST BY
THE ECMWF.  THE NHC FORECAST IS BASICALLY AN UPDATE OF THE
PREVIOUS ONE...STILL A BIT FASTER AND WEST OF THE MODEL CONSENSUS.  
 
GLOBAL MODELS SHOW THIS SYSTEM BECOMING RATHER LARGE...SO THE WIND
RADII FORECAST HAS BEEN SIGNIFICANTLY EXPANDED.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  30/2100Z 14.4N  45.3W   40 KT  45 MPH
 12H  31/0600Z 15.3N  47.6W   50 KT  60 MPH
 24H  31/1800Z 16.5N  50.6W   60 KT  70 MPH
 36H  01/0600Z 17.7N  53.6W   70 KT  80 MPH
 48H  01/1800Z 19.0N  56.1W   75 KT  85 MPH
 72H  02/1800Z 22.0N  59.5W   85 KT 100 MPH
 96H  03/1800Z 26.0N  61.0W   85 KT 100 MPH
120H  04/1800Z 28.5N  60.5W   85 KT 100 MPH
 
$$
FORECASTER BLAKE
 
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