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| #202409 (Received by flhurricane at: 11:09 PM 21.Jul.2008) TCDAT4 TROPICAL STORM DOLLY DISCUSSION NUMBER 7 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL042008 1100 PM EDT MON JUL 21 2008 DOLLY HAS CONTINUED TO GENERATE DEEP CONVECTION NEAR THE CORE THIS EVENING...AND NOW SHOWS EVIDENCE OF WRAPPING A BAND IN THE SOUTHERN SEMICIRCLE AGAINST THE EASTERLY SHEAR...WHICH HAS BEEN DECREASING. DATA FROM THE NOAA AIRCRAFT...HOWEVER...INDICATE THAT THE SURFACE CENTER IS SOUTH OF THE APPARENT INFRARED CENTER. DOLLY IS ALSO MOVING OVER A WARM GULF EDDY. GIVEN THESE CHANGES...STRENGTHENING SHOULD BEGIN VERY SOON. THE UPPER-LEVEL FLOW IS NOT YET IDEAL FOR DEVELOPMENT...WITH THE ANTICYCLONE LOCATED TO THE EAST OF DOLLY...BUT THE GLOBAL MODELS FORECAST THESE FEATURES TO BECOME BETTER CONNECTED JUST BEFORE LANDFALL. ON THE OTHER HAND...DOLLY IS EXPECTED TO ENCOUNTER A COLD EDDY IN ABOUT 18-24 HOURS...WHEN THE FORWARD SPEED IS EXPECTED TO BE QUITE A BIT SLOWER THAN IT IS NOW...AND THIS ENCOUNTER COULD PROVIDE A DAMPER ON THE INTENSIFICATION RATE IN THE LAST HOURS PRIOR TO LANDFALL. THE BOTTOM LINE OF ALL THIS IS THAT DOLLY VERY LIKELY WILL BECOME A HURRICANE...BUT THE ODDS ARE AGAINST IT BECOMING A MAJOR HURRICANE. THE INITIAL MOTION IS 280/15. THE GUIDANCE MODELS FROM YESTERDAY DID A NICE JOB IN FORECASTING THE INCREASE IN SPEED TODAY...AND ARE IN EXCELLENT AGREEMENT THAT THE FORWARD MOTION WILL SLOW SIGNIFICANTLY TOMORROW AS THE UPPER LOW TO THE SOUTH OF DOLLY WEAKENS ALONG WITH THE UPPER-LEVEL EASTERLIES. THE MID-LEVEL RIDGE OVER EAST TEXAS IS FORECAST TO ERODE SLIGHTLY AS A PAIR OF MID-LATITUDE SHORT WAVES MOVE THROUGH THE GREAT LAKES. THIS IS EXPECTED TO CAUSE A BEND OF THE TRACK TO THE RIGHT OVER THE NEXT 24-36 HOURS. MODEL GUIDANCE IS FAIRLY TIGHTLY CLUSTERED AND THE OFFICIAL FORECAST IS IN THE MIDDLE OF THE GUIDANCE ENVELOPE...WITH THE GFS TO THE SOUTH AND THE GFDL TO THE NORTH. FORECAST POSITIONS AND MAX WINDS INITIAL 22/0300Z 23.1N 92.8W 45 KT 12HR VT 22/1200Z 23.9N 94.4W 55 KT 24HR VT 23/0000Z 24.8N 95.8W 65 KT 36HR VT 23/1200Z 25.6N 96.9W 75 KT 48HR VT 24/0000Z 26.2N 98.0W 50 KT...INLAND 72HR VT 25/0000Z 26.5N 101.5W 25 KT...REMNANT LOW 96HR VT 26/0000Z...DISSIPATED $$ FORECASTER FRANKLIN |
