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#9134 (Received by flhurricane at: 10:46 AM 18.Sep.2004) TCDAT1 TROPICAL STORM JEANNE DISCUSSION NUMBER 20 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT SAT SEP 18 2004 SATELLITE IMAGES INDICATE THAT THE CLOUD PATTERN ASSOCIATED WITH JEANNE IS GRADUALLY RECOVERING FROM THE INTERACTION WITH HISPANIOLA. THE LOW-LEVEL CENTER IS LOCATED UNDER THE INCREASING CONVECTION AND T-NUMBERS ARE UP TO 3.0 ON THE DVORAK SCALE. LATEST AIRCRAFT MEASURED A FLIGHT LEVEL WIND OF 54 KNOTS AND GRAND TURK HAS REPORTED 41 KNOTS. BASED ON THIS INFORMATION...THE INITIAL INTENSITY HAS BEEN INCREASED TO 45 KNOTS. WATER VAPOR IMAGES SHOW AN UPPER-LOW SWINGING SOUTHWARD AROUND THE WESTERN PORTION OF JEANNE. THIS PATTERN WOULD RESULT IN THE RELAXATION OF THE SHEAR FOLLOWED BY SOME STRENGTHENING. JEANNE HAS THE CHANCE TO REGAIN HURRICANE STATUS IN THE NEXT DAY OR TWO BEFORE THE SHEAR INCREASES AGAIN. THE OFFICIAL FORECAST GOES ALONG WITH BOTH SHIPS AND THE GFDL. JEANNE IS MOVING VERY SLOWLY TOWARD THE NORTH-NORTHWEST OR 340 DEGREES AT 6 KNOTS AROUND THE PERIPHERY OF A WEAK SUBTROPICAL RIDGE. A SHARP MID-TO UPPER LEVEL TROUGH...PARTIALLY RELATED TO IVAN...IS EXPECTED TO BE MOVING EASTWARD CREATING A WEAKNESS TO THE NORTH OF THE CYCLONE. THIS PATTERN WOULD FORCE JEAN TO MOVE ON A GENERAL NORTHWARD TRACK DURING THE NEXT 3 DAYS. THEREAFTER...A RATHER STRONG HIGH IS EXPECTED TO REPLACE THE TROUGH AND DEPENDING HOW FAR NORTH JEANNE MOVES...THE CYCLONE COULD BE BLOCKED AND MOVE WESTWARD OR COULD TURN NORTHEASTWARD FOLLOWING THE TROUGH. SINCE THERE IS MUCH UNCERTAINTY IN GLOBAL MODELS BEYOND 3 DAYS...THE BEST OPTION AT THIS TIME IS TO KEEP JEAN NEARLY STATIONARY BETWEEN BERMUDA AND THE BAHAMAS AT DAYS 4 AND 5. IN FACT...THE GFS KEEP THE CYCLONE LOOPING WITHIN THIS REGION THROUGH THE PERIOD. FORECASTER AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 18/1500Z 21.4N 73.0W 45 KT 12HR VT 19/0000Z 22.2N 73.2W 55 KT 24HR VT 19/1200Z 23.5N 73.5W 60 KT 36HR VT 20/0000Z 25.0N 73.5W 65 KT 48HR VT 20/1200Z 26.5N 73.5W 70 KT 72HR VT 21/1200Z 28.0N 73.5W 65 KT 96HR VT 22/1200Z 29.0N 73.0W 65 KT 120HR VT 23/1200Z 29.1N 73.0W 65 KT |