000 WTNT42 KNHC 091435 TCDAT2 TROPICAL STORM LESLIE DISCUSSION NUMBER 41 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 1100 AM AST SUN SEP 09 2012 LESLIE HAS A VERY BROAD EYE AS EVIDENCED BY BERMUDA RADAR OBSERVATIONS AND SATELLITE IMAGES. A RECENT ASCAT PASS OVER THE TROPICAL CYCLONE SHOWED 40-45 KT WINDS...AND ENHANCED IR DATA SHOWED SOME INCREASE IN THE DEEP CONVECTION IN CLUSTERS SURROUNDING THE CENTER. THE CURRENT INTENSITY IS HELD AT 50 KT FOR THIS ADVISORY. SINCE LESLIE LACKS A WELL-DEFINED INNER CORE...IT MAY HAVE DIFFICULTY RE-INTENSIFYING AS IT MOVES FARTHER AWAY FROM THE COOLER WATERS IT UPWELLED. HOWEVER...UPPER-TROPOSPHERIC WINDS ARE FORECAST TO BE FAVORABLE FOR STRENGTHENING DURING THE NEXT DAY OR SO...AND THE OFFICIAL WIND SPEED FORECAST SHOWS THE CYCLONE REGAINING HURRICANE STATUS AS IN THE PREVIOUS ADVISORY. THIS IS ALSO IN GOOD AGREEMENT WITH THE LATEST LGEM GUIDANCE. BEYOND 48 HOURS...THE GLOBAL MODELS DEPICT LESLIE TO BE QUITE DEEP BUT BECOMING EMBEDDED WITHIN A FRONTAL ZONE...SO THE SYSTEM IS FORECAST TO BECOME A VIGOROUS EXTRATROPICAL CYCLONE IN 2-3 DAYS AS IT MOVES OVER THE ATLANTIC. BY DAY 5 THE SYSTEM IS LIKELY TO MERGE WITH A LARGE LOW TO THE NORTHWEST OF SCANDANAVIA. LESLIE IS BEGINNING TO INCREASE ITS FORWARD SPEED...AND THE INTIAL MOTION IS ESTIMATED TO BE 010/9. AS A MID-TROPOSPHERIC TROUGH MOVES OFF THE NORTHEAST U.S. COAST...THE CYCLONE IS EXPECTED TO ACCELERATE NORTH-NORTHEASTWARD IN THE FLOW ON THE EAST SIDE OF THE TROUGH OVER THE NEXT COUPLE OF DAYS. IN 3-4 DAYS...THE POST- TROPICAL CYCLONE SHOULD TURN EAST-NORTHEASTWARD IN THE HIGHER LATITUDE WESTERLIES. THE OFFICIAL TRACK FORECAST IS SOMEWHAT FASTER THAN THE PREVIOUS ONE IN THE LATTER PART OF THE FORECAST PERIOD...BUT NOT AS FAST AS THE LATEST GFS SOLUTION. LONG-PERIOD SWELLS FROM LESLIE ARE EXPECTED TO PRODUCE ROUGH SURF AND LIFE-THREATENING RIP CURRENTS ON BERMUDA AND ALONG MUCH OF THE U.S. EAST COAST FOR THE NEXT FEW DAYS. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 32.0N 62.4W 50 KT 60 MPH 12H 10/0000Z 33.6N 62.0W 55 KT 65 MPH 24H 10/1200Z 36.3N 60.9W 60 KT 70 MPH 36H 11/0000Z 40.2N 59.0W 65 KT 75 MPH 48H 11/1200Z 46.5N 55.5W 65 KT 75 MPH 72H 12/1200Z 58.0N 42.0W 65 KT 75 MPH...POST-TROP/EXTRATROP 96H 13/1200Z 62.0N 20.0W 55 KT 65 MPH...POST-TROP/EXTRATROP 120H 14/1200Z...MERGED $$ FORECASTER PASCH