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#9458 (Received by flhurricane at: 5:26 PM 21.Sep.2004) TCDAT1 HURRICANE JEANNE DISCUSSION NUMBER 33 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT TUE SEP 21 2004 VISIBLE AND INFRARED SATELLITE IMAGERY...ALONG WITH DVORAK INTENSITY ESTIMATES...INDICATE JEANNE HAS CHANGED LITTLE DURING THE PAST 6 HOURS. THE RAGGED EYE HAS BEEN INTERMITTENTLY CLOUD-COVERED AND THE SATELLITE INTENSITY ESTIMATE REMAINS T4.5...OR 77KT...FROM TAFB AND SAB. AS SUCH...THE INTENSITY ALSO REMAINS AT 80 KT. AN AIR FORCE RESERVE RECON FLIGHT WILL INVESTIGATE JEANNE AGAIN AT 22/06Z. THE INITIAL MOTION IS NOW 140/05. AGAIN...THERE REMAINS NO SIGNIFICANT CHANGE TO THE PREVIOUS FORECAST TRACK OR REASONING. THE NHC MODEL GUIDANCE IS IN BETTER AGREEMENT NOW...EXCEPT FOR THE GFS...ON JEANNE MAKING A SLOW ANTICYCLONIC LOOP DURING THE NEXT 36-48 HOURS BEFORE MOVING NORTHWEST AND EVENTUALLY NORTHWARD. WHILE THE GFS IS STILL THE EASTERNMOST OUTLIER MODEL...EVEN IT HAS CONTINUED TO SHIFT ITS TRACK FARTHER WEST CLOSER TO THE REST OF THE OTHER MODELS. THE DEEP-LAYERED HIGH PRESSURE SYSTEM OVER THE EASTERN U.S. IS SLOWLY BUILDING SOUTH AND EASTWARD TO THE NORTH OF JEANNE AS A LARGE TROUGH TO THE NORTHEAST OF THE CYCLONE CONTINUES TO SHIFT EASTWARD. THE OFFICIAL TRACK IS SIMILAR TO THE PREVIOUS TWO FORECASTS...AND IS CLOSE TO THE GUNS CONSENSUS MODEL. THE VERTICAL SHEAR ACROSS JEANNE IS STILL FORECAST TO WEAKEN TO LESS THAN 10 KT IN 36-48 HOURS...SO SOME SLIGHT STRENGTHENING IS POSSIBLE AROUND THAT TIME. BY 72 HOURS...HOWEVER...SIGNIFICANT VERTICAL SHEAR FROM THE SOUTH AND SOUTHWEST IS FORECAST TO SPREAD ACROSS JEANNE AS THE HURRICANE MOVES UNDERNEATH THE WESTERN PERIPHERY OF A STRONG 200 MB ANTICYCLONE. THEREFORE...GRADUAL WEAKENING IS EXPECTED. HWOEVERE...IF JEANNE SHOULD MOVE A LITTLE FASTER AND A FARTHER WEST LIKE THE NOGAPS MODEL IS FORECASTING... THEN THE HURRICANE WOULD LIKELY WEAKEN EVEN MORE THAN FORECAST SINCE IT WOULD BE UNDER STRONGER UPPER-LEVEL FLOW. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 21/2100Z 27.3N 68.8W 80 KT 12HR VT 22/0600Z 27.0N 68.7W 80 KT 24HR VT 22/1800Z 26.5N 68.7W 80 KT 36HR VT 23/0600Z 26.2N 69.0W 85 KT 48HR VT 23/1800Z 26.4N 69.6W 85 KT 72HR VT 24/1800Z 27.3N 71.3W 80 KT 96HR VT 25/1800Z 29.0N 73.5W 70 KT 120HR VT 26/1800Z 32.0N 74.5W 60 KT |