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| #7194 (Received by flhurricane at: 10:32 PM 02.Sep.2004) TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT THU SEP 02 2004 WHILE I AM NOT CRAZY ABOUT RELOCATING A TROPICAL CYCLONE AT NIGHT...AN SSMI PASS NEAR 23Z SUGGESTS THAT THE CENTER OF THE DEPRESSION IS FARTHER EAST THAN PREVIOUSLY THOUGHT...NEAR THE NORTHEAST EDGE OF THE DEEP CONVECTION. ANALYSES FROM CIMSS SHOW ABOUT 15 KT OF NORTHEASTERLY SHEAR OVER THE DEPRESSION...CONSISTENT WITH THIS POSITIONING OF THE CENTER. THE DEPRESSION HAS BEEN MAINTAINING A BALL OF VERY COLD CONVECTION FOR THE LAST SEVERAL HOURS...AND DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB AT 00Z WERE 30 KT. HOWEVER...THESE ESTIMATES WERE BASED ON POSITIONS MORE EMBEDDED IN THE CONVECTION...AND SO I AM INCLINED TO KEEP THE INITIAL INTENSITY AT 25 KT. WITH THE RELOCATION OF THE CENTER...THE INITIAL MOTION IS NOW ESTIMATED TO BE 270/12. THE DEPRESSION IS EMBEDDED IN A DEEP EASTERLY FLOW SOUTH OF THE SUBTROPICAL RIDGE...WHICH IS FORECAST TO BE MAINTAINED THROUGHOUT THE FORECAST PERIOD. THERE IS GOOD AGREEMENT AMONG THE GFDL...UKMET...AND GFS MODELS ON A BRISK WESTWARD MOTION WHICH HAS BEEN FOLLOWED CLOSELY FOR THIS ADVISORY. THE NOGAPS IS CONSIDERABLY SLOWER THAN THE REST OF THE GUIDANCE... BUT APPEARS TO BE HAVING TROUBLE CONSOLIDATING A CIRCULATION DURING THE FIRST COUPLE DAYS OF THE INTEGRATION...AND HAS BEEN DISCOUNTED. THE OFFICIAL FORECAST IS A LITTLE SLOWER THAN THE PREVIOUS ADVISORY AS A RESULT OF THE RELOCATION AND CHANGE IN THE INITIAL MOTION. THE GFDL HAS UNBRIDLED ENTHUSIASM FOR THIS SYSTEM...TAKING THE DEPRESSION TO CATEGORY FOUR STATUS IN ABOUT THREE DAYS. BOTH THE GFS AND UKMET SUGGEST THAT THE EASTERLY SHEAR WILL BE SLOW TO DIMINISH AS THE DEPRESSION REMAINS ON THE SOUTH SIDE OF AN UPPER-LEVEL ANTICYCLONE. STEADY STRENGTHENING WILL BE FORECAST...BUT MORE IN LINE WITH THE SHIPS MODEL GUIDANCE. FORECASTER FRANKLIN FORECAST POSITIONS AND MAX WINDS INITIAL 03/0300Z 9.8N 29.4W 25 KT 12HR VT 03/1200Z 9.9N 31.5W 35 KT 24HR VT 04/0000Z 10.1N 34.7W 45 KT 36HR VT 04/1200Z 10.4N 38.0W 50 KT 48HR VT 05/0000Z 10.8N 41.0W 55 KT 72HR VT 06/0000Z 11.5N 47.5W 65 KT 96HR VT 07/0000Z 12.5N 53.5W 75 KT 120HR VT 08/0000Z 14.0N 59.5W 80 KT |
