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| #35233 (Received by flhurricane at: 10:58 PM 24.Jul.2005) TCDAT1 TROPICAL STORM FRANKLIN DISCUSSION NUMBER 15 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT SUN JUL 24 2005 FRANKLIN IS BEING AFFECTED BY STRONG NORTHWESTERLY VERTICAL WIND SHEAR THIS EVENING. THE LOW-LEVEL CENTER IS NOW COMPLETELY EXPOSED...AND THE CONVECTIVE BURSTS TO THE SOUTHEAST ARE GENERALLY GETTING FARTHER AWAY FROM THE CENTER. SATELLITE INTENSITY ESTIMATES ARE 45 KT FROM TAFB...AND 35 KT FROM SAB AND AFWA. BASED ON THESE...THE INITIAL INTENSITY IS REDUCED TO 40 KT. INTERESTING CHANGES HAVE OCCURRED IN THE MOTION THIS EVENING. FRANKLIN STOPPED MOVING EAST-NORTHEASTWARD JUST AFTER 18Z...AND FOR THE PAST SEVERAL HOURS HAS DRIFTED SOUTH-SOUTHWEST. THIS MOTION... WHICH WAS POORLY FORECAST BY THE DYNAMICAL GUIDANCE...IS LIKELY DUE TO A BUILDING LOW-LEVEL RIDGE NORTH OF FRANKLIN IN THE WAKE OF THE PREVIOUS UPPER-LEVEL TROUGH AND COLD FRONT. LARGE-SCALE MODELS FORECAST THIS RIDGE TO START WEAKENING IN 12 HR OR SO IN FRONT OF THE NEXT MID-LATITUDE TROUGH...WHICH SHOULD ALLOW FRANKLIN TO RESUME THE EAST-NORTHEASTWARD MOTION FORECAST BY THE DYNAMICAL MODELS. THIS MOTION WILL LIKELY BE UNSTEADY...AS THE NEW TROUGH WILL LIKELY NOT BE STRONG ENOUGH TO WHISK FRANKLIN AWAY AND A FINAL NORTHEASTWARD ACCELERATION MAY HAVE TO WAIT FOR A THIRD TROUGH IN 3-4 DAYS TIME. THE OFFICIAL FORECAST TRACK IS SLOWER AND SHIFTED SOUTHWARD FROM THE PREVIOUS FORECAST. IT SHOULD BE NOTED THAT THE SHALLOW-STEERING BAMS CALLS FOR FRANKLIN TO DO A LOOP BETWEEN BERMUDA AND THE U. S. FOR THE NEXT 5 DAYS. THE UPPER-LEVEL ENVIRONMENT IS CURRENTLY UNFAVORABLE...AND IF THE GFS AND THE CANADIAN ARE CORRECT IT WILL NOT BE GETTING FAVORABLE FOR AT LEAST 48-72 HR. THE UKMET AND NOGAPS FORECAST A LESS HOSTILE...ALTHOUGH LESS THAN IDEAL...UPPER-LEVEL WIND PATTERN AFTER 48 HR...WHICH COULD ALLOW FRANKLIN TO RE-INTENSIFY IF THOSE MODELS ARE CORRECT. THE SHIPS MODEL FORECASTS STEADY WEAKENING THROUGH 120 HR...WHILE THE GFDL AND GFDN SHOW SOME INTENSIFICATION AFTER 24-36 HR. THE INTENSITY FORECAST WILL GO WITH THE SHIPS SCENARIO...BUT MAINTAIN A HIGHER INTENSITY THAN THE SHIPS FORECAST DUE TO THE UNCERTAINTIES IN THE FORECAST UPPER-LEVEL WINDS. THE STALLING DELAYS THE NEED FOR TROPICAL STORM WATCHES OF WARNING FOR BERMUDA. HOWEVER...THEY MAY BE REQUIRED ON MONDAY. FORECASTER BEVEN FORECAST POSITIONS AND MAX WINDS INITIAL 25/0300Z 30.9N 71.6W 40 KT 12HR VT 25/1200Z 30.8N 71.6W 40 KT 24HR VT 26/0000Z 31.0N 70.3W 35 KT 36HR VT 26/1200Z 31.7N 68.5W 35 KT 48HR VT 27/0000Z 32.5N 67.2W 30 KT 72HR VT 28/0000Z 34.0N 65.0W 25 KT 96HR VT 29/0000Z 36.5N 61.5W 25 KT 120HR VT 30/0000Z 40.0N 55.0W 25 KT...DISSIPATING |
