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#4155 (Received by flhurricane at: 4:59 PM 10.Aug.2004) TCDAT3 TROPICAL STORM CHARLEY DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 PM EDT TUE AUG 10 2004 THERE HAS BEEN A SIGNIFICANT SHIFT IN OUR TRACK GUIDANCE FOR CHARLEY THIS AFTERNOON. IT APPEARS THAT THE DYNAMICAL MODELS ARE SHOWING A GREATER INFLUENCE OF THE EASTERN UNITED STATES TROUGH THAN IN EARLIER RUNS...ERODING MORE OF THE WESTERN PERIPHERY OF THE SUBTROPICAL RIDGE AND ALLOWING THE TROPICAL CYCLONE TO CURVE NORTHWARD SOONER THAN EARLIER ANTICIPATED. BASED ON THIS GUIDANCE CHANGE...THE OFFICIAL TRACK FORECAST HAS BEEN SHIFTED SUBSTANTIALLY TO THE RIGHT OF THE PREVIOUS ONES. THIS IS A LITTLE WEST OF THE DYNAMICAL MODEL CONSENSUS AND CLOSE TO THE LATEST NOGAPS RUN. ALSO...SINCE THE FORWARD SPEED HAS NOT SLOWED THUS FAR...THE NHC FORECAST IS FASTER THAN THE PREVIOUS ONE. NEAR THE END OF THE FORECAST PERIOD...IF CHARLEY FOLLOWS THE INDICATED TRACK...THE SPEED MAY VERY WELL BE TOO SLOW BUT THERE IS CONSIDERABLE UNCERTAINTY IN JUST WHERE THIS SYSTEM WILL END UP IN 3-5 DAYS. IF THE GUIDANCE FOR THE NEXT PACKAGE IS SIMILAR...THE OFFICIAL TRACK MAY HAVE BE SHIFTED A LITTLE FARTHER TO THE EAST. ON THEIR FIRST PENETRATION INTO THIS STORM...THE HURRICANE HUNTERS REPORTED A 999 MB CENTRAL PRESSURE. THE AIRCRAFT HAS NOT YET SAMPLED ALL QUADRANTS OF THE TROPICAL CYCLONE...BUT BASED ON THIS PRESSURE READING THE WINDS HAVE BEEN INCREASED A LITTLE. THE UPPER-LEVEL OUTFLOW LOOKS STRONG AND THE SHEAR IS EXPECTED TO REMAIN WEAK OVER THE NEXT FEW DAYS. THEREFORE CONDITIONS APPEAR TO BE FAVORABLE FOR INTENSIFICATION. DEEP CONVECTION IS CURRENTLY RATHER WEAK...BUT THIS MAY VERY WELL BE A DIURNAL FLUCTUATION. THE OFFICIAL FORECAST SHOWS CONTINUED STRENGTHENING BUT REMAINS MORE CONSERVATIVE THAN THE SHIPS GUIDANCE. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 10/2100Z 15.2N 70.8W 45 KT 12HR VT 11/0600Z 16.3N 74.0W 50 KT 24HR VT 11/1800Z 17.7N 77.4W 55 KT 36HR VT 12/0600Z 19.4N 80.0W 55 KT 48HR VT 12/1800Z 21.0N 82.0W 65 KT 72HR VT 13/1800Z 25.0N 83.5W 75 KT 96HR VT 14/1800Z 29.0N 83.5W 85 KT 120HR VT 15/1800Z 33.0N 81.5W 25 KT...INLAND |