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| #540148 (Received by flhurricane at: 4:35 PM 04.Sep.2012) TCDAT2 TROPICAL STORM LESLIE DISCUSSION NUMBER 22 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 500 PM AST TUE SEP 04 2012 ALTHOUGH DEEP CONVECTION HAS REDEVELOPED NEAR THE CENTER OF LESLIE DURING THE DAY...THE LOW-LEVEL CENTER IS STILL SOMEWHAT DISPLACED TO THE WEST OF THE MID- AND UPPER-LEVEL CENTER. THE CI-NUMBERS FROM TAFB AND SAB REMAIN 3.5 AND A RECENT ASCAT PASS SHOWED BIAS-CORRECTED WINDS OF 50-55 KT...SO THE INITIAL INTENSITY IS HELD AT 55 KT. 20 KT OF WEST-NORTHWESTERLY VERTICAL WIND SHEAR...AS ANALYZED BY THE UW-CIMSS AND SHIPS SHEAR ANALYSIS...CONTINUES TO BE THE PRIMARY INHIBITING FACTOR FOR DEVELOPMENT. THE SHEAR IS FORECAST TO RELAX AFTER 36 HOURS...WHICH SHOULD ALLOW FOR INTENSIFICATION. ADDITIONALLY...THE UNIVERSITY OF MIAMI-RSMAS OCEAN ANALYSIS INDICATES THAT THE HEAT CONTENT OF THE OCEAN BELOW LESLIE IS HIGH...WHICH MAY LIMIT THE IMPACTS OF COLD WATER UPWELLING FROM THE SLOW-MOVING CYCLONE. THE FORECAST CALLS FOR STEADY INTENSIFICATION AFTER 36 HOURS...AND IS CLOSE TO THE LGEM MODEL FORECAST. BY DAY 5...THE OFFICIAL FORECAST IS HIGHER THAN MOST OF THE NUMERICAL GUIDANCE...HOWEVER...GIVEN THE EXPECTED FAVORABLE ENVIRONMENT AROUND THE CYCLONE...THE INTENSITY FORECAST HAS NOT BEEN ADJUSTED DOWN AT THIS TIME. WHILE THE CENTER HAS WOBBLED SLIGHTLY TO THE WEST DURING THE DAY...LESLIE CONTINUES TO DRIFT GENERALLY NORTHWARD AND THE LONG- TERM INITIAL MOTION IS ESTIMATED AT 360/3. THIS TRACK IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS UNTIL A RIDGE BEGINS TO BUILD TO THE NORTHEAST OF THE TROPICAL CYCLONE...IMPARTING A MORE NORTHWESTERLY MOTION. LESLIE SHOULD FINALLY BEGIN TO ACCELERATE AS IT MOVES AROUND THIS RIDGE ON DAYS 4 AND 5. THE GLOBAL AND REGIONAL DYNAMICAL MODELS ARE SHOWING A SLIGHTLY SLOWER AND WESTWARD TRACK THIS CYCLE AND THE OFFICIAL FORECAST HAS BEEN NUDGED ACCORDINGLY. THE 34- AND 50-KT WIND RADII WERE MODIFIED BASED ON A 1320 UTC ASCAT PASS. DUE TO THE LARGE SIZE OF LESLIE AND ITS EXPECTED SLOW MOTION... LARGE SWELLS PROPAGATING AWAY FROM THE TROPICAL CYCLONE WILL CONTINUE TO AFFECT BERMUDA AND NEARLY ALL OF THE U.S. EAST COAST FOR MUCH OF THIS WEEK. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 25.3N 62.6W 55 KT 65 MPH 12H 05/0600Z 25.7N 62.7W 55 KT 65 MPH 24H 05/1800Z 26.1N 62.7W 55 KT 65 MPH 36H 06/0600Z 26.5N 62.7W 55 KT 65 MPH 48H 06/1800Z 26.9N 62.8W 60 KT 70 MPH 72H 07/1800Z 27.5N 63.5W 70 KT 80 MPH 96H 08/1800Z 29.5N 65.0W 80 KT 90 MPH 120H 09/1800Z 34.0N 65.5W 90 KT 105 MPH $$ FORECASTER ZELINSKY/CANGIALOSI |
