000 WTNT42 KNHC 302036 TCDAT2 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