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| #37901 (Received by flhurricane at: 10:40 AM 06.Aug.2005) TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 8 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 AM EDT SAT AUG 06 2005 THERE HAS BEEN LITTLE CHANGE IN THE OVERALL STRUCTURE OF THE DEPRESSION THIS MORNING...EXCEPT THAT MULTIPLE SWIRLS HAVE BEEN APPARENT NEAR THE MEAN CIRCULATION CENTER. THIS MORNING'S QUIKSCAT PASS MISSED THE DEPRESSION. THE ADVISORY INTENSITY WILL REMAIN 30 KT...IN ACCORD WITH THE PASS FROM LAST NIGHT. CONVECTION NEAR THE CENTER IS CURRENTLY VERY LIMITED DUE TO WESTERLY SHEAR...DRY AIR...AND RELATIVELY COOL SSTS. NONE OF THESE CONDITIONS ARE EXPECTED TO CHANGE MUCH OVER THE NEXT DAY OR SO...HOWEVER...THE DEPRESSION WILL BE MOVING OVER 28C WATER IN ABOUT 48 HOURS. A TRACK TO THE SOUTH OF THE OFFICIAL FORECAST WOULD ALSO KEEP THE SYSTEM AWAY FROM THE WESTERLY SHEAR. THE OFFICIAL FORECAST IS VERY CLOSE TO THE SHIPS GUIDANCE...ALTHOUGH IT IS WORTH NOTING THAT THE GFDL GRADUALLY FADES THIS SYSTEM AWAY. THE INITIAL MOTION IS 285/10...A LITTLE SLOWER THAN BEFORE. THE TRACK FORECAST REMAINS PROBLEMATIC. A WEAKNESS IN THE 500 MB RIDGE ASSOCIATED WITH TROPICAL STORM HARVY SHOULD BE NORTH OF THE DEPRESSION IN ABOUT 48 HOURS. MUCH OF THE GUIDANCE...LED BY THE NOGAPS...LIFTS THE DEPRESSION INTO THIS WEAKNESS. THE GFS ACTUALLY SPLITS THE DEPRESSION...TAKING A PIECE NORTHWARD INTO THE WEAKNESS BUT ALSO CARRYING A WEAK WAVE WEST-NORTHWESTWARD. IT IS HARD TO BE CONFIDENT AT THIS POINT ABOUT THE LONG-RANGE TRACK FORECAST. IN THE INTEREST OF CONTINUITY THE OFFICIAL FORECAST IS CLOSE TO THE PREVIOUS ADVISORY AND NEAR THE DYNAMICAL MODEL CONSENSUS. HOWEVER...SATELLITE IMAGES OVER THE PAST HOUR OR SO ARE SUGGESTING THAT THE CIRCULATION CENTER IS BECOMING BETTER DEFINED ABOUT 45 NMI TO THE NORTH OF MY ADVISORY POSITION. IF THIS TURNS OUT TO BE THE DOMINANT CENTER...THEN A NORTHWARD ADJUSTMENT OF THE TRACK MAY BE REQUIRED THIS AFTERNOON. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 06/1500Z 17.9N 42.3W 30 KT 12HR VT 07/0000Z 18.3N 43.8W 30 KT 24HR VT 07/1200Z 18.9N 46.0W 30 KT 36HR VT 08/0000Z 19.4N 48.0W 30 KT 48HR VT 08/1200Z 20.4N 50.0W 35 KT 72HR VT 09/1200Z 22.0N 53.0W 40 KT 96HR VT 10/1200Z 23.5N 56.0W 45 KT 120HR VT 11/1200Z 25.5N 59.0W 50 KT |
