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#605471 (Received by flhurricane at: 10:38 PM 06.Jun.2013) TCDAT1 TROPICAL STORM ANDREA DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012013 1100 PM EDT THU JUN 06 2013 ANDREA HAS WEAKENED CONSIDERABLY SINCE MOVING INLAND EARLIER THIS EVENING. THE ONLY REPORT OF TROPICAL-STORM-FORCE WINDS ON LAND OR OVER WATER HAS COME FROM A SHIP OBSERVATION EAST OF SAINT AUGUSTINE...AND THE INITIAL INTENSITY HAS BEEN LOWERED TO 40 KT. ANY WINDS THIS STRONG ARE LIKELY OCCURRING IN RANBANDS OFFSHORE TO THE EAST OF THE CENTER. THE SATELLITE PRESENTATION OF ANDREA BEARS LITTLE RESEMBLANCE TO A TROPICAL CYCLONE...WITH A PRONOUNCED DRY INTRUSION NOTED OVER AND SOUTHWEST OF THE CENTER AND THE DEEP CONVECTION IN A BAND WELL REMOVED TO THE EAST AND SOUTHEAST. GIVEN THAT ONLY SHALLOW CONVECTION IS OCCURRING NEAR THE CENTER... INTERACTION WITH BAROCLINIC FEATURES WILL INCREASINGLY BECOME THE MECHANISM SUPPORTING THE CYCLONE THROUGH THE FORECAST PERIOD. AS ANDREA IS ABSORBED BY A LIFTING MID/UPPER-LEVEL TROUGH...GLOBAL MODEL GUIDANCE SHOWS LITTLE CHANGE IN INTENSITY DURING THE FORECAST PERIOD. THE NEW NHC FORECAST FOLLOWS THIS THINKING...AND SHOWS ANDREA BECOMING POST-TROPICAL BY 24 HOURS. HOWEVER...THIS COULD OCCUR SOONER IF THE CONVECTIVE STRUCTURE DOES NOT IMPROVE. THE INITIAL MOTION IS 045/13...AS THE CENTER SLOWED A LITTLE WHILE MOVING ONSHORE. THE TRACK MODEL GUIDANCE REMAINS IN VERY GOOD AGREEMENT SHOWING THE CYCLONE ACCELERATING NORTHEASTWARD ALONG THE U.S. EAST COAST AHEAD OF THE AFOREMENTIONED TROUGH AND THEN TURNING QUICKLY EASTWARD OVER THE NORTH ATLANTIC. THE NEW NHC FORECST IS A LITTLE TO THE RIGHT OF THE PREVIOUS ONE FOR THE FIRST 24 HOURS DUE TO THE INITIAL MOTION AND IS LARGELY AN UPDATE OF THE PREVIOUS PACKAGE AFTERWARD. THE NHC TRACK IS CLOSE TO A BLEND OF THE GFS AND ECMWF AND ALSO LIES NEAR THE FSU SUPERENSEMBLE. BASED ON THE ASSUMPTION THAT ANDREA WILL BECOME POST-TROPICAL IN ABOUT 24 HOURS...WE DO NOT EXPECT TO EXTEND THE TROPICAL WARNINGS ANY FARTHER NORTH ALONG THE COAST. OUR CURRENT INTENTION IS THAT ANY HAZARDOUS WIND CONDITIONS FROM THE DELMARVA PENINSULA NORTHWARD TO NEW ENGLAND WOULD BE HANDLED BY LOCAL NATIONAL WEATHER SERVICE WARNING PRODUCTS. FORECAST POSITIONS AND MAX WINDS INIT 07/0300Z 30.3N 82.4W 40 KT 45 MPH...INLAND 12H 07/1200Z 33.0N 80.2W 40 KT 45 MPH...INLAND 24H 08/0000Z 36.8N 76.3W 40 KT 45 MPH...POST-TROPICAL 36H 08/1200Z 41.0N 70.7W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 09/0000Z 44.7N 63.3W 35 KT 40 MPH...POST-TROP/EXTRATROP 72H 10/0000Z 45.5N 46.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 96H 11/0000Z 45.5N 24.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 120H 12/0000Z...DISSIPATED $$ FORECASTER BRENNAN |