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| #9168 (Received by flhurricane at: 4:46 PM 18.Sep.2004) TCDAT1 TROPICAL STORM JEANNE DISCUSSION NUMBER 21 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT SAT SEP 18 2004 HIGH RESOLUTION SATELLITE IMAGES SHOW THAT THE LOW-LEVEL CENTER OF JEANNE THAT WAS TRACKED SINCE IT MOVED AWAY FROM HISPANIOLA HAS RUN WESTWARD AHEAD OF THE CONVECTION...AND IS DISSIPATING. SURFACE DATA FROM THE BAHAMAS AND FROM A RECONNAISSANCE PLANE INDICATE THAT A NEW CENTER HAS REFORMED UNDER THE CONVECTION WELL TO THE NORTHEAST OF THE PREVIOUS LOCATION. THIS BY NO MEANS INDICATES A NORTHEASTWARD MOTION OF THE CYCLONE. THE INITIAL INTENSITY IS ESTIMATED AT 40 KNOTS BASED ON SURFACE OBSERVATIONS FROM GRAND TURK. AN UPPER-LOW WHICH GLOBAL MODELS WERE FORECASTING TO MOVE SOUTH AND WEAKEN...INSTEAD MOVED OVER THE CYCLONE AND AMPLYFIED... DISRUPTING THE CLOUD PATTERN. THIS RESULTED IN WEAKENING. NOW THIS NEW CENTER LOCATION IS UNDER A LITTLE MORE FAVORABLE ENVIRONMENT AND GLOBAL MODELS INSIST ON THE DEVELOPMENT OF AN UPPER-LEVEL ANTICYLONE OVER THE SYSTEM. THIS SUGGESTS STRENGTHENING AS INDICATED IN THE OFFICIAL FORECAST AND GOES ALONG WITH BOTH SHIPS AND THE GFDL MODELS. THE TRACK FORECAST REASONING HAS NOT CHANGED. IT IS ONLY BEING SHIFTED EASTWARD DUE TO THE REFORMATION. JEANNE IS FORECAST TO MOVE TOWARD THE NORTH-NORTHWEST AND NORTH ABOUT 6 KNOTS FOR 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 JEANNE NEARLY STATIONARY BETWEEN BERMUDA AND THE BAHAMAS AT DAYS THREE THROUGH FIVE. IN FACT...NOW ALL THE RELIABLE GLOBAL MODELS...THE GFS...THE UKMET AND NOGAPS KEEP THE CYCLONE LOOPING WITHIN THIS REGION THROUGH THE PERIOD OR LONGER. FORECASTER AVILA FORECAST POSITIONS AND MAX WINDS INITIAL 18/2100Z 22.0N 72.3W 40 KT 12HR VT 19/0600Z 22.9N 72.5W 40 KT 24HR VT 19/1800Z 24.1N 72.6W 40 KT 36HR VT 20/0600Z 25.7N 72.5W 50 KT 48HR VT 20/1800Z 27.0N 72.5W 60 KT 72HR VT 21/1800Z 28.5N 71.5W 65 KT 96HR VT 22/1800Z 28.5N 71.5W 65 KT 120HR VT 23/1800Z 28.5N 71.5W 65 KT |
