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| #201507 (Received by flhurricane at: 4:55 PM 17.Jul.2008) TCDAT2 TROPICAL STORM BERTHA DISCUSSION NUMBER 59 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL022008 500 PM EDT THU JUL 17 2008 SATELLITE IMAGES INDICATE THAT BERTHA IS MAINTAINING ITS STRUCTURE AS A TROPICAL STORM WITH DEFINED BANDING FEATURES AND OUTFLOW ALOFT. CONVECTION HAS BEEN WELL-MAINTAINED...ESPECIALLY IN THE NORTHEAST QUADRANT OF THE STORM. THERE HAS BEEN NO CHANGE IN THE SATELLITE CLASSIFICATIONS SO THE INITIAL INTENSITY WILL REMAIN 50 KT. NO SIGNIFICANT INTENSITY FLUCTUATIONS ARE EXPECTED DURING THE NEXT DAY OR SO AS THE STORM REMAINS UNDER THE INFLUENCE OF MODERATE SHEAR AND WANING SSTS. THE EXTRATROPICAL TRANSITION PROCESS SHOULD START SHORTLY AFTER 48 HR DUE TO AN INCREASE IN SHEAR AND MORE RAPIDLY DECREASING SSTS...AND BY 120 HR...THE REMNANTS OF BERTHA WILL LIKELY BE ABSORBED INTO A LARGER EXTRATROPICAL LOW. THE STORM HAS MADE AN EASTWARD TURN AND IS MOVING ABOUT 090/10. A BUILDING RIDGE TO THE EAST OF BERTHA SHOULD STEER THE STORM MORE TO THE NORTHEAST TOMORROW...FOLLOWING CLOSE BEHIND A MIDDLE- TO UPPER-LEVEL LOW TO ITS NORTH. MODEL GUIDANCE IS TIGHTLY CLUSTERED ON AN ACCELERATING PATH OUT TO SEA. THE GFS HAS CHANGED FROM THE SOUTH TO NORTH SIDE OF THE MODEL CONSENSUS...NOW SHOWING MORE INTERACTION WITH A NEW MIDDLE-LATITUDE TROUGH IN A COUPLE OF DAYS. THE OFFICIAL FORECAST LIES ON THE LEFT SIDE OF THE CONSENSUS AND IS PRETTY CLOSE TO THE PREVIOUS ONE. TO CLARIFY A PREVIOUS DISCUSSION COMMENT...BERTHA COULD BECOME ONE OF THE TOP 10 LONGEST-LIVED ATLANTIC STORMS...IN TERMS OF DAYS AS A TROPICAL STORM OR GREATER...IF IT SURVIVES UNTIL SUNDAY. FORECAST POSITIONS AND MAX WINDS INITIAL 17/2100Z 34.0N 57.2W 50 KT 12HR VT 18/0600Z 34.4N 55.6W 45 KT 24HR VT 18/1800Z 35.9N 53.3W 45 KT 36HR VT 19/0600Z 37.8N 51.0W 45 KT 48HR VT 19/1800Z 39.9N 48.3W 45 KT 72HR VT 20/1800Z 45.0N 41.0W 50 KT...EXTRATROPICAL 96HR VT 21/1800Z 53.5N 30.0W 50 KT...EXTRATROPICAL 120HR VT 22/1800Z...ABSORBED $$ FORECASTER BLAKE |
