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#605775 (Received by flhurricane at: 4:53 PM 07.Jun.2013) TCDAT1 POST-TROPICAL CYCLONE ANDREA DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012013 500 PM EDT FRI JUN 07 2013 SURFACE OBSERVATIONS AND DOPPLER RADAR DATA INDICATE THAT ANDREA IS NO LONGER TROPICAL. DEEP CONVECTION OVER NORTH CAROLINA APPEARS TO BE ASSOCIATED MORE WITH A FRONTAL ZONE THAN THE CYCLONE ITSELF...AND THE LOW-LEVEL CENTER HAS BEGUN TO LOSE DEFINITION. HOWEVER...EVEN THOUGH THE CYCLONE IS BEING DECLARED POST-TROPICAL...ADVISORIES FROM NHC WILL CONTINUE UNTIL THE SYSTEM NO LONGER POSES A SIGNIFICANT THREAT TO THE U.S. EAST COAST. THE INITIAL INTENSITY REMAINS 40 KT...WHICH IS SUPPORTED BY A PARTIAL ASCAT PASS FROM 1448 UTC. TROPICAL STORM CONDITIONS ARE PRIMARILY CONFINED TO THE ATLANTIC WATERS AND COASTAL AREAS OF NORTH CAROLINA AND EXTREME SOUTHEASTERN VIRGINIA. THE INTENSITY GUIDANCE CONTINUES TO SHOW ANDREA CHANGING LITTLE IN STRENGTH AS IT MOVES UP THE U.S. EAST COAST...AND THE OFFICIAL INTENSITY FORECAST IS UNCHANGED FROM THE PREVIOUS ONE. GLOBAL MODEL GUIDANCE IS SHOWING ANDREA BEING STRETCHED OVER THE NORTH ATLANTIC IN 24-48 HOURS...WITH A SECOND LOW PRESSURE SYSTEM BECOMING THE MORE DOMINANT SYSTEM AND ABSORBING ANDREA BY 72 HOURS EAST OF NEWFOUNDLAND. THE INITIAL MOTION IS 040/24 KT. ANDREA WILL CONTINUE TO ACCELERATE NORTHEASTWARD DURING THE NEXT 24 HOURS WHILE IT BECOMES INCREASINGLY EMBEDDED IN STRONG MID-LATITUDE FLOW. THE SPREAD AMONG THE TRACK GUIDANCE REMAINS RELATIVELY SMALL...AND THE UPDATED NHC TRACK FORECAST IS VERY SIMILAR TO THE PREVIOUS ONE. IT SHOULD BE STRESSED THAT EVEN THOUGH ANDREA HAS BECOME POST-TROPICAL...THE THREAT FOR HIGH WINDS...HEAVY RAINFALL...AND LOCALIZED COASTAL FLOODING WILL CONTINUE THROUGH SATURDAY ACROSS THE MID-ATLANTIC STATES AND NEW ENGLAND. HAZARDOUS CONDITIONS FROM THE DELMARVA PENINSULA NORTHWARD TO NEW ENGLAND WILL CONTINUE TO BE COMMUNICATED THROUGH LOCAL NATIONAL WEATHER SERVICE WARNING PRODUCTS. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 36.1N 77.8W 40 KT 45 MPH...POST-TROP/EXTRATROP 12H 08/0600Z 39.3N 74.1W 40 KT 45 MPH...POST-TROP/EXTRATROP 24H 08/1800Z 43.4N 67.6W 40 KT 45 MPH...POST-TROP/EXTRATROP 36H 09/0600Z 46.0N 60.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 09/1800Z 46.9N 51.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 72H 10/1800Z...ABSORBED BY ANOTHER LOW $$ FORECASTER BERG/BEVEN |