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#539320 (Received by flhurricane at: 10:53 AM 01.Sep.2012) TCDAT2 TROPICAL STORM LESLIE DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 1100 AM AST SAT SEP 01 2012 VISIBLE SATELLITE IMAGES SHOW THAT LESLIE REMAINS A SHEARED CYCLONE WITH THE LOW-LEVEL CENTER DISPLACED TO THE NORTHWEST OF THE MAIN CONVECTIVE BAND. THE INITIAL WIND SPEED IS KEPT AT 60 KT AS A COMPROMISE BETWEEN THE VARIOUS INTENSITY ESTIMATES. IT SEEMS LIKE THE WINDOW FOR LESLIE TO BECOME A HURRICANE IS CLOSING AS NORTHWESTERLY SHEAR HAS INCREASED. THIS SHEAR IS EVIDENT IN CIRRUS CLOUD MOTIONS NEAR THE CENTER...ALONG WITH LARGE-SCALE ANALYSES FROM THE SHIPS MODEL AND UW-CIMSS. THE GLOBAL MODELS SUGGEST THIS SHEAR WILL PERSIST OR EVEN INTENSIFY DURING THE NEXT COUPLE OF DAYS AS LESLIE IS CAUGHT ON THE EASTERN SIDE OF AN UPPER-LEVEL ANTICYCLONE. THE NHC INTENSITY FORECAST IS REDUCED DURING THAT TIME...AND IS IN BEST AGREEMENT WITH THE INTENSITY CONSENSUS AND THE FSU SUPERENSEMBLE. THERE ARE SOME INDICATIONS THAT THE SHEAR COULD RELAX IN A FEW DAYS...SO GRADUAL STRENGTHENING IS SHOWN IN THE LONG RANGE...CONTINUING THE TREND OF THE PREVIOUS FORECAST. MICROWAVE AND VISIBLE IMAGES REQUIRE A REPOSITIONING OF LESLIE ABOUT 30 N MI WEST OF THE PREVIOUS FIXES...GIVING A LONG-TERM MOTION OF ABOUT 290/16. THE CYCLONE SHOULD TURN TO THE NORTHWEST BY TOMORROW AS IT MOVES AROUND A WEAKENING RIDGE OVER THE CENTRAL ATLANTIC OCEAN...THEN TURN NORTHWARD IN A FEW DAYS AS IT NEARS A BREAK IN THE RIDGE. THE GLOBAL MODELS ARE A BIT FASTER IN GENERAL...SHOWING ENOUGH RIDGING EAST OF LESLIE TO KEEP THE SYSTEM FROM TOTALLY STALLING OUT AS SUGGESTED IN EARLIER MODEL CYCLES. THE NEW NHC FORECAST IS A BIT FASTER AND LEFT OF THE PREVIOUS ONE...MOSTLY DUE TO THE CENTER REPOSITIONING. THE INITIAL AND FORECAST WIND RADII WERE ADJUSTED BASED ON A 1244 UTC ASCAT PASS. FORECAST POSITIONS AND MAX WINDS INIT 01/1500Z 18.3N 55.7W 60 KT 70 MPH 12H 02/0000Z 19.4N 57.6W 60 KT 70 MPH 24H 02/1200Z 21.0N 59.8W 60 KT 70 MPH 36H 03/0000Z 22.7N 61.2W 60 KT 70 MPH 48H 03/1200Z 24.1N 62.1W 60 KT 70 MPH 72H 04/1200Z 26.0N 62.5W 65 KT 75 MPH 96H 05/1200Z 27.5N 62.0W 70 KT 80 MPH 120H 06/1200Z 29.0N 61.5W 75 KT 85 MPH $$ FORECASTER BLAKE |