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#442677 (Received by flhurricane at: 10:52 PM 18.Jul.2011) TCDAT2 TROPICAL STORM BRET DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL022011 1100 PM EDT MON JUL 18 2011 THE AIR FORCE RESERVE HURRICANE HUNTER MISSION FROM EARLIER THIS AFTERNOON MADE ONE MORE PASS THROUGH THE CENTER OF BRET AFTER THE RELEASE OF THE 2100 UTC ADVISORY AND ESSENTIALLY FOUND LITTLE CHANGE TO THE WINDS. HOWEVER...THE CENTRAL PRESSURE INCREASED BY 1 MB ON EACH SUCCESSIVE PASS OF THE AIRCRAFT...AND THE INTENSITY OF THE DEEP CONVECTION HAS BEEN ON A DOWNWARD TREND OVER THE PAST FEW HOURS. THE INTENSITY ON THIS ADVISORY IS THEREFORE LOWERED TO 50 KT. MOST OF THE INTENSITY GUIDANCE STILL GIVES BRET THE OPPORTUNITY FOR SOME RE-STRENGTHENING DURING THE NEXT 12 HOURS OR SO...AND THE OFFICIAL FORECAST INDICATES THIS POSSIBILITY SHOULD THE DEEP CONVECTION RE-DEVELOP OVERNIGHT. MORE CERTAIN WEAKENING SHOULD COMMENCE BEYOND 24 HOURS AS THE VERTICAL SHEAR BECOMES INCREASINGLY HOSTILE...AND BRET IS EXPECTED TO DISSIPATE WITHIN SOUTHWESTERLY MID-LATITUDE FLOW SOUTH OF THE CANADIAN MARITIMES BY DAY 5. BRET STILL APPEARS TO BE MOVING AT AN AVERAGE MOTION OF 030/6. THE CYCLONE IS EXPECTED TO ACCELERATE NORTHEASTWARD AROUND THE NORTHWESTERN PERIPHERY OF A MID-LEVEL HIGH...BUT THE TRACK GUIDANCE IS A LITTLE SLOWER ON THIS MOTION FOR THIS FORECAST CYCLE. THE ECMWF IS THE FASTEST OF THE GUIDANCE...BUT IT IS NOW 12 HOURS OLD AND...ALONG WITH OFCI...FELL VERY NEAR THE EDGE OF THE GPCE CIRCLE FAR FROM THE OTHER RELIABLE MODELS AT 72 HOURS. THE NEW OFFICIAL TRACK FORECAST IS SHIFTED IN THE DIRECTION OF THE MODEL CONSENSUS AND IS THEREFORE ON TRACK WITH BUT A LITTLE SLOWER THAN THE PREVIOUS NHC FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 19/0300Z 28.7N 76.6W 50 KT 60 MPH 12H 19/1200Z 29.5N 76.1W 55 KT 65 MPH 24H 20/0000Z 30.6N 75.1W 55 KT 65 MPH 36H 20/1200Z 31.7N 73.8W 50 KT 60 MPH 48H 21/0000Z 33.1N 71.9W 50 KT 60 MPH 72H 22/0000Z 36.0N 67.0W 40 KT 45 MPH 96H 23/0000Z 39.0N 59.0W 30 KT 35 MPH 120H 24/0000Z...DISSIPATED $$ FORECASTER BERG |