000 WTNT42 KNHC 040256 TCDAT2 TROPICAL STORM LESLIE DISCUSSION NUMBER 19 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 1100 PM AST MON SEP 03 2012 WEST-NORTHWESTERLY SHEAR CONTINUES TO KEEP THE STORM FROM BECOMING BETTER ORGANIZED...WITH THE MAIN MASS OF DEEP CONVECTION DISPLACED TO THE SOUTHEAST OF THE ESTIMATED CENTER LOCATION. HOWEVER...A RECENT ASCAT OVERPASS INDICATES THAT SOME SLIGHT STRENGTHENING HAS OCCURRED...AND BASED ON THE SCATTEROMETER DATA THE CURRENT INTENSITY IS SET TO 55 KT. THIS IS ALSO CONSISTENT WITH THE LATEST DVORAK ESTIMATES FROM TAFB AND SAB. NOT MUCH ADDITIONAL INTENSIFICATION IS LIKELY IN THE SHORT TERM AS THE DYNAMICAL GUIDANCE DOES NOT SHOW THE SHEAR RELAXING SIGNIFICANTLY FOR THE NEXT 24 TO 36 HOURS. LATER ON...HOWEVER...THE GLOBAL MODELS ARE INSISTENT THAT THE UPPER-LEVEL WIND PATTERN WILL BECOME MORE CONDUCIVE FOR STRENGTHENING...AS THE GFS DEPICTS A WELL-DEFINED AND SYMMETRICAL UPPER-TROPOSPHERIC ANTICYCLONE BECOMING ESTABLISHED OVER LESLIE IN ABOUT 72 HOURS. THE OFFICIAL INTENSITY FORECAST IS SIMILAR TO THAT FROM THE PREVIOUS ADVISORY...AND IS CLOSE TO A BLEND OF THE LATEST LGEM AND SHIPS PREDICTIONS. MICROWAVE AND GEOSTATIONARY SATELLITE FIXES INDICATE THAT THE STORM HAS MOVED VERY LITTLE...IF AT ALL...SO THE INTIAL MOTION ESTIMATE IS STATIONARY. LESLIE IS EXPECTED TO MOVE QUITE SLOWLY IN A GENERAL NORTHWARD DIRECTION WHILE IT REMAINS IN VERY WEAK STEERING CURRENTS FOR A GOOD PART OF THE FORECAST PERIOD. BY ABOUT 5 DAYS...THE FLOW BETWEEN A MID-TROPOSPHERIC TROUGH OVER THE EASTERN U.S. AND AN ANTICYCLONE TO THE NORTHEAST OF THE TROPICAL CYCLONE SHOULD INDUCE A SLIGHTLY FASTER NORTH-NORTHWESTWARD MOTION. THE OFFICIAL TRACK FORECAST IS ABOUT THE SAME AS THAT FROM THE PREVIOUS ADVISORY AND REMAINS CLOSE TO THE MULTI-MODEL CONSENSUS TVCN. BUOY OBSERVATIONS SHOW THAT WAVES GREATER THAN 12 FEET HIGH EXTEND SOME 300-400 N MI FROM THE CENTER. DUE TO THE LARGE SIZE OF THE TROPICAL CYCLONE AND ITS EXPECTED SLOW MOTION...LARGE SWELLS PROPAGATING AWAY FROM LESLIE WILL AFFECT BERMUDA AND NEARLY ALL OF THE U.S. EAST COAST FOR MUCH OF THE WEEK. FORECAST POSITIONS AND MAX WINDS INIT 04/0300Z 24.0N 63.1W 55 KT 65 MPH 12H 04/1200Z 24.6N 63.2W 55 KT 65 MPH 24H 05/0000Z 25.3N 63.2W 55 KT 65 MPH 36H 05/1200Z 25.8N 63.2W 55 KT 65 MPH 48H 06/0000Z 26.3N 63.2W 60 KT 70 MPH 72H 07/0000Z 27.2N 63.5W 70 KT 80 MPH 96H 08/0000Z 28.5N 64.0W 80 KT 90 MPH 120H 09/0000Z 31.0N 65.0W 85 KT 100 MPH $$ FORECASTER PASCH