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| #35670 (Received by flhurricane at: 5:00 AM 27.Jul.2005) TCDAT1 TROPICAL STORM FRANKLIN DISCUSSION NUMBER 24 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT WED JUL 27 2005 THE LOW LEVEL CENTER OF FRANKLIN HAS ONCE AGAIN BECOME EXPOSED... TO THE NORTH OF A LIMITED AREA OF CONVECTION THAT IS STILL FAIRLY DEEP... WITH TOPS AS COLD AS ABOUT -70 DEGREES CELSIUS. WHILE THE SYSTEM IS SHEARED... THE LOW LEVEL CENTER IS STILL CLOSE ENOUGH TO THE CONVECTION SUCH THAT DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB REMAIN 35 KT... SO FRANKLIN HANGS ON AS A 35 KT TROPICAL STORM ON THIS ADVISORY. WHILE THE CONVECTION HAS NOT MOVED MUCH DURING THE PAST FEW HOURS... THE LOW LEVEL CENTER HAS BEEN MOVING STEADILY TOWARD THE NORTH AT ABOUT 6 KT. THIS COULD BE THE END OF THE ERRATIC MOTION AND THE START OF THE LONG-AWAITED ACCELERATION TO THE NORTH AND EVENTUALLY THE NORTHEAST... AHEAD OF THE MIDLATITUDE TROUGH AND ATTENDANT COLD FRONT NOW APPROACHING THE NORTHEASTERN UNITED STATES. IT WILL PROBABLY TAKE FRANKLIN ABOUT 24 MORE HOURS... WHILE A RIDGE BUILDS TO ITS EAST AND THE TROUGH APPROACHES FROM THE WEST... TO BEGIN MOVING MUCH FASTER AND MORE NORTHEASTWARD THAN IT IS CURRENTLY. THE VARIOUS DYNAMICAL MODELS GENERALLY AGREE ON THIS SCENARIO... ALTHOUGH THEY CONTINUE TO DISAGREE ON FORWARD SPEED LATER IN THE FORECAST. DUE TO THE FASTER THAN EXPECTED INITIAL MOTION... THE NEW TRACK IS FASTER THAN THE PREVIOUS ADVISORY BUT SLOWER THAN THE MODEL CONSENSUS... WITH WHICH I AM RELATIVELY COMFORTABLE GIVEN THAT THE MODELS HAVE BEEN TOO FAST THE LAST COUPLE OF DAYS TO SEND FRANKLIN OFF TO THE RACES. IT DOES NOT SEEM THAT THE ENVIRONMENT... IN TERMS OF VERTICAL WIND SHEAR... WILL BECOME MUCH MORE FAVORABLE FOR STRENGTHENING DURING THE NEXT COUPLE OF DAYS ALONG THE FORECAST TRACK BEFORE FRANKLIN REACHES COOLER WATERS. THE INTENSITY FORECAST IS THEREFORE KEPT LEVEL AT 35 KT... WHICH IS A COMPROMISE BETWEEN THE GFDL AND SHIPS GUIDANCE... UNTIL FRANKLIN BECOMES EXTRATROPICAL AND EVENTUALLY BECOMES ABSORBED BY A LARGER EXTRATROPICAL SYSTEM DURING THE NEXT THREE TO FOUR DAYS. FORECASTER KNABB FORECAST POSITIONS AND MAX WINDS INITIAL 27/0900Z 33.1N 68.8W 35 KT 12HR VT 27/1800Z 34.1N 68.8W 35 KT 24HR VT 28/0600Z 35.7N 68.2W 35 KT 36HR VT 28/1800Z 37.6N 66.9W 35 KT 48HR VT 29/0600Z 39.7N 64.5W 35 KT...BECOMING EXTRATROPICAL 72HR VT 30/0600Z 43.5N 56.5W 30 KT...EXTRATROPICAL 96HR VT 31/0600Z...ABSORBED BY EXTRATROPICAL SYSTEM |
