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#604837 (Received by flhurricane at: 6:05 PM 05.Jun.2013) TCDAT1 TROPICAL STORM ANDREA SPECIAL DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL012013 600 PM EDT WED JUN 05 2013 THE AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INVESTIGATING THE LARGE AREA OF DISTURBED WEATHER OVER THE EASTERN GULF OF MEXICO HAS FOUND A CIRCULATION CENTER LOCATED NEAR THE WESTERN EDGE OF THE LARGE MASS OF THUNDERSTORMS. THIS CENTER APPEARS TO HAVE FORMED VERY RECENTLY SO THE INITIAL MOTION ESTIMATE IS UNCERTAIN. THE AIRCRAFT MEASURED AN EXTRAPOLATED SURFACE PRESSURE OF 1002 MB...PEAK 1000 FT FLIGHT-LEVEL WINDS OF 47 KT...AND BELIEVABLE BIAS-CORRECTED SFMR SURFACE WINDS OF AROUND 35 KT. THESE DATA SUPPORT AN INITIAL INTENSITY OF 35 KT. STRONG SOUTHWESTERLY SHEAR IS EXPECTED TO CONTINUE DURING THE NEXT COUPLE OF DAYS AND SIGNIFICANT STRENGTHENING APPEARS UNLIKELY. THE INTENSITY FORECAST SHOWS LITTLE OVERALL CHANGE IN STRENGTH...EVEN AFTER THE SYSTEM BECOMES EXTRATROPICAL IN 2 TO 3 DAYS. ANDREA IS FORECAST TO MOVE SLOWLY NORTHWARD TONIGHT...THEN ACCELERATE NORTHEASTWARD ON THURSDAY AHEAD OF A MID- TO UPPER-LEVEL TROUGH MOVING INTO THE SOUTHEASTERN UNITED STATES. THE GLOBAL MODELS ARE IN GOOD AGREEMENT ON THIS GENERAL SCENARIO...ALTHOUGH THEY ALSO SUGGEST THE POSSIBILITY OF JUMPS OR REFORMATIONS OF THE CENTER DURING THE NEXT 24 HOURS. LANDFALL ALONG THE COAST OF THE FLORIDA BIG BEND ON THURSDAY AFTERNOON OR EVENING IS EXPECTED. AFTER THAT...THE SYSTEM IS FORECAST TO ACCELERATE NORTHEASTWARD ALONG THE COAST OF THE SOUTHEAST UNITED STATES. THERE WILL BE SOME BAROCLINIC FORCING BY THAT TIME...BUT IT IS UNCLEAR WHEN ANDREA WILL BECOME POST-TROPICAL. THE NHC FORECAST SHOWS ANDREA REMAINING A TROPICAL CYCLONE THROUGH 48 HOURS...BUT THE TRANSITION TO A POST-TROPICAL CYCLONE COULD OCCUR SOONER. THE CURRENT FORECAST REQUIRES THE ISSUANCE OF A TROPICAL STORM WARNING ALONG THE WEST COAST OF THE FLORIDA PENINSULA AND A TROPICAL STORM WATCH ALONG THE SOUTHEAST UNITED STATES COAST. THE PRIMARY EFFECTS FROM ANDREA ARE EXPECTED TO BE HEAVY RAINFALL ACROSS MUCH OF THE FLORIDA PENINSULA...STORM SURGE FLOODING ALONG PORTIONS OF THE WEST COAST OF FLORIDA...AND ISOLATED TORNADOES LATE TONIGHT AND THURSDAY ACROSS THE FLORIDA PENINSULA. THE PRONUNCIATION OF THIS NAME IS ANN- DREE UH. FORECAST POSITIONS AND MAX WINDS INIT 05/2200Z 25.3N 86.5W 35 KT 40 MPH 12H 06/0600Z 26.5N 86.4W 35 KT 40 MPH 24H 06/1800Z 28.3N 85.0W 40 KT 45 MPH 36H 07/0600Z 31.0N 82.0W 40 KT 45 MPH...INLAND 48H 07/1800Z 34.5N 78.5W 40 KT 45 MPH...INLAND 72H 08/1800Z 43.0N 67.5W 40 KT 45 MPH...POST-TROP/EXTRATROP 96H 09/1800Z 45.0N 48.0W 40 KT 45 MPH...POST-TROP/EXTRATROP 120H 10/1800Z 47.0N 25.0W 40 KT 45 MPH...POST-TROP/EXTRATROP $$ FORECASTER BROWN |