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#631023 (Received by flhurricane at: 10:56 PM 10.Sep.2013) TCDAT2 TROPICAL STORM GABRIELLE DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072013 1100 PM AST TUE SEP 10 2013 SATELLITE IMAGERY SHOWS THAT THE PRIMARY AREA OF DEEP CONVECTION ASSOCIATED WITH GABRIELLE HAS BECOME DISPLACED WELL TO THE EAST OF THE LOW-LEVEL CENTER THIS EVENING...DUE TO STRONG SOUTHWESTERLY SHEAR. RADAR IMAGES FROM BERMUDA HAVE BEEN EXTREMELY HELPFUL IN TRACKING THE PROGRESS OF THE STORM THIS EVENING. THE RADAR DATA SHOW THAT GABRIELLE HAS DECELERATED AND THAT SOME SHALLOW CONVECTIVE BANDS ARE WRAPPING AROUND THE NORTHEASTERN PORTION OF THE CIRCULATION. THE INITIAL WIND SPEED REMAINS 50 KT...WHICH IS BASED ON THE EARLIER AIRCRAFT DATA AND RECENT OBSERVATIONS OF 35 TO 45 KT SUSTAINED WINDS AT WEATHER STATIONS ON BERMUDA. ANOTHER AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT WILL BE INVESTIGATING THE TROPICAL STORM OVERNIGHT. THE INITIAL MOTION ESTIMATE IS 355/7 KT. GABRIELLE SHOULD TURN NORTH-NORTHWESTWARD ON WEDNESDAY AS IT IS STEERED AROUND THE NORTHEASTERN SIDE OF A MID- TO UPPER-LEVEL LOW LOCATED EAST OF FLORIDA. IN A COUPLE OF DAYS...THE DEEP LAYER FLOW OFF THE EAST COAST OF THE UNITED STATES IS FORECAST TO TURN SOUTHWESTWARD AND STRENGTHEN AHEAD OF A MID-LATITUDE TROUGH. THIS SHOULD CAUSE GABRIELLE TO TURN NORTHEASTWARD AND BEGIN TO ACCELERATE. THE TRACK MODEL GUIDANCE IS IN GENERAL AGREEMENT ON THIS SCENARIO...BUT HAS SHIFTED A LITTLE WESTWARD DURING THE FIRST 36 HOURS. CONSEQUENTLY...THE NHC TRACK HAS BEEN NUDGED WESTWARD TO BE IN BETTER AGREEMENT WITH THE GUIDANCE. AFTER 36 HOURS...THE UPDATED NHC TRACK IS CLOSE TO THE PREVIOUS ADVISORY. GABRIELLE IS FORECAST TO REMAIN OVER WARM WATER BUT WITHIN MODERATE TO STRONG SOUTHWESTERLY SHEAR DURING THE NEXT FEW DAYS. THE SHEAR IS LIKELY TO PREVENT ANY SIGNIFICANT STRENGTHENING AND THE LATEST INTENSITY GUIDANCE NOW SHOWS LITTLE CHANGE IN STRENGTH DURING THE NEXT DAY OR SO. AS A RESULT...THE NHC INTENSITY FORECAST HAS BEEN ADJUSTED SLIGHTLY LOWER. IF ORGANIZED DEEP CONVECTION DOES NOT REDEVELOP IN ASSOCIATION WITH THE CYCLONE... GABRIELLE COULD DEGENERATE INTO A REMNANT LOW TOMORROW. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 32.0N 65.0W 50 KT 60 MPH 12H 11/1200Z 32.8N 65.3W 50 KT 60 MPH 24H 12/0000Z 33.6N 66.0W 45 KT 50 MPH 36H 12/1200Z 34.5N 66.6W 45 KT 50 MPH 48H 13/0000Z 36.3N 66.6W 45 KT 50 MPH 72H 14/0000Z 44.5N 61.5W 45 KT 50 MPH 96H 15/0000Z 54.0N 47.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 16/0000Z...DISSIPATED $$ FORECASTER BROWN |