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| #34979 (Received by flhurricane at: 5:08 PM 23.Jul.2005) TCDAT1 TROPICAL STORM FRANKLIN DISCUSSION NUMBER 10 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT SAT JUL 23 2005 FRANKLIN HAS CHANGED LITTLE IN SATELLITE IMAGERY SINCE THE LAST RECON REPORT AROUND 17Z. AN 850 MB FLIGHT-LEVEL WIND OF 63 KT WAS REPORTED ABOUT 50 NMI SOUTH OF THE CENTER AT 1543Z...AND SUBSEQUENT DROPSONDE WIND PROFLIES ELSEWHERE SUGGEST THAT THE STANDARD 80 PERCENT REDUCTION FACTOR MAY BE TOO HIGH AND THAT USING 100 PERCENT MAY BE MORE REPRESENTATIVE. GIVEN THAT THE CENTRAL PRESSURE HAD NOT FALLEN BELOW 1000 MB ALL DAY...THE INITIAL INTENSITY WILL BE MAINTAINED AT 60 KT FOR THIS ADVISORY. WIND RADII WERE EXPANDED TO THE SOUTHEAST BASED ON THE RECON WIND AND DROPSONDE DATA. THE INITIAL MOTION ESTIMATE IS 060/08. FRANKLIN HAS BEEN MOVING STEADILY TO THE NORTHEAST AND EAST-NORTHEAST FOR THE PAST 12 HOURS OR SO AS THE MID-LEVEL FLOW TO THE WEST OF THE CYCLONE HAS BECOME WEST TO WEST-NORTHWESTERLY. THE NEW 12Z MODEL GUIDANCE CREATES SOMETHING OF A QUANDARY WITH THE TRACK FORECAST. THE SHORTWAVE TROUGH CURRENTLY ALONG THE U.S. EAST COAST IS FORECAST BY ALL THE MODELS TO LIFT OUT TO THE NORTHEAST OF FRANKLIN AND LEAVE AT LEAST A WELL-DEFINED MID-LEVEL CIRCULATION BEHIND BY 36-48 HOURS. AFTER THAT...THE MID-LEVEL CIRCULATION IS FORECAST TO REMAIN NEARLY STATIONARY AND THEN DRIFT SOUTH OR SOUTHWESTWARD BY 96 HOURS... WHILE THE LOW-LEVEL CIRCULATION MOVES NORTHEASTWARD. IF FRANKLIN REMAINS INTACT AT 72 HOURS...THEN THE SOUTHWARD MOTION IS QUITE POSSIBLE GIVEN THAT ALL THE MODELS INDICATE THE MID-LEVEL FLOW WILL GRADUALLY BECOME NORTHWESTERLY AND THEN NORTHERLY. THE OFFICIAL FORECAST IS SLOWER AND TO THE RIGHT OF THE PREVIOUS FORECAST... AND A LITTLE SLOWER THAN THE GUNS AND GUNA MODELS. FRANKLIN COULD STILL BECOME A 65-KT HURRICANE WITHIN THE NEXT 24 HOURS BEFORE INCREASING NORTHERLY UPPER-LEVEL SHEAR STARTS TO AFFECT THE CYCLONE. EVEN IF THE CYCLONE DOES TURN SOUTHWARD...THE UPPER-LEVEL SHEAR IS EXPECTED TO REMAIN UNFAVORABLE FOR ANY SIGNIFICANT INTENSIFICATION TO OCCUR UNTIL AFTER 72 HOURS WHEN THE 200 MB FLOW IS FORECAST TO WEAKEN AND A SMALL ANTICYCLONE MOVES ACROSS THE SYSTEM. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 23/2100Z 29.9N 74.3W 60 KT 12HR VT 24/0600Z 30.4N 73.0W 65 KT 24HR VT 24/1800Z 30.8N 71.5W 65 KT 36HR VT 25/0600Z 31.2N 69.6W 60 KT 48HR VT 25/1800Z 31.4N 68.0W 55 KT 72HR VT 26/1800Z 32.1N 65.3W 50 KT 96HR VT 27/1800Z 33.5N 62.5W 45 KT 120HR VT 28/1800Z 35.0N 59.5W 40 KT |
