|
Show Selection: |
| #30271 (Received by flhurricane at: 11:18 PM 05.Jul.2005) TCDAT4 TROPICAL STORM DENNIS DISCUSSION NUMBER 5 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT TUE JUL 05 2005 DENNIS HAS CONTINUED TO GET BETTER ORGANIZED AND HAS INTENSIFIED DURING THE PAST 6 HOURS. A NOAA RECON REPORT AT 650 MB INDICATED FLIGHT-LEVEL WINDS OF 45 KT IN THE NORTHEAST QUADRANT AT 05/2114Z AND A CENTRAL PRESSURE OF 1001 MB. USING ABOUT 95 PERCENT OF THE FLIGHT-LEVEL WINDS AND A T3.0/45 KT SATELLITE INTENSITY ESTIMATE FROM TAFB AND SAB SUPPORT INCREASING THE INITIAL INTENSITY TO 45 KT. UPPER-LEVEL OUTFLOW REMAINS IMPRESSIVE IN ALL QUADRANTS. THE INITIAL MOTION ESTIMATE IS 295/15. DENNIS HAS SLOWED ITS FORWARD SPEED SOMEWHAT...POSSIBLY DUE TO RE-ORGANIZATION OF THE DEEP CONVECTION AROUND THE CENTER. THE NHC MODEL GUIDANCE REMAINS TIGHTLY CLUSTERED ABOUT THE PREVIOUS FORECAST TRACKS AND TAKES DENNIS BETWEEN HAITI AND JAMAICA AND THEN BETWEEN JAMAICA AND SOUTHEASTERN CUBA THROUGH 72 HOURS AS THE CYCLONE MOVES AROUND THE SOUTHWEST PERIPHERY OF A DEEP-LAYERED SUBTROPICAL RIDGE THAT LIES EAST-WEST ACROSS THE WESTERN ATLANTIC AND FLORIDA. HOWEVER...AFTER THAT...THE FORECAST BECOMES A LITTLE MURKY. ALL OF THE MODELS WEAKEN THE WESTERN PORTION OF THE RIDGE OVER FLORIDA AS A SHARP SHORTWAVE TROUGH OVER THE CENTRAL U.S. DIGS SOUTHEASTWARD INTO THE CENTRAL GULF OF MEXICO BY DAYS 4 AND 5...BEFORE LIFTING OUT SLOWLY TO THE NORTHEAST AFTER THAT. SINCE DENNIS IS A LARGER THAN AVERAGE TROPICAL CYCLONE THAT IS FORECAST TO BECOME A MAJOR HURRICANE IN DAYS 3-5...THE LARGE OUTER CIRCULATION COULD ERODE THE RIDGE EVEN MORE...RESULTING IN WEAKER STEERING CURRENTS THAN THE 5-8 KT THAT THE MODELS ARE FORECASTING. THE OFFICIAL TRACK IS ALMOST IDENTICAL TO THE PREVIOUS FORECAST AND IS ALONG THE EXTREME EASTERN..OR RIGHT...SIDE OF THE MODEL GUIDANCE ENVELOPE. DENNIS IS EXPECTED TO REMAIN IN A VERY LOW SHEAR AND HIGH SST ENVIRONMENT..WHICH UNFORTUNATELY ARE PRIME CONDITIONS FOR PRODUCING INTENSE HURRICANES. THE OFFICIAL INTENSITY FORECAST IS MUCH HIGHER THAN THE PREVIOUS FORECASTS...BUT IS LESS THAN THE SHIPS AND GFDL INTENSITY MODELS...WHICH BRING DENNIS TO 108 KT IN 96 HOURS AND 113 KT IN 60 HOURS...RESPECTIVELY. FORECASTER STEWART FORECAST POSITIONS AND MAX WINDS INITIAL 06/0300Z 14.6N 69.2W 45 KT 12HR VT 06/1200Z 15.8N 71.3W 55 KT 24HR VT 07/0000Z 17.4N 74.0W 70 KT 36HR VT 07/1200Z 18.8N 76.5W 80 KT 48HR VT 08/0000Z 20.1N 78.8W 90 KT 72HR VT 09/0000Z 22.4N 82.4W 100 KT 96HR VT 10/0000Z 24.5N 84.5W 100 KT 120HR VT 11/0000Z 27.0N 86.5W 100 KT |
