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#6038 (Received by flhurricane at: 11:52 PM 24.Aug.2004) TCDAT1 TROPICAL DEPRESSION SIX DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 11 PM EDT TUE AUG 24 2004 SATELLITE IMAGERY SHOWS THAT THE CLOUD PATTERN ASSOCIATED WITH THE STRONG TROPICAL WAVE OVER THE EASTERN ATLANTIC HAS BECOME BETTER ORGANIZED OVER THE PAST SEVERAL HOURS...WITH AN INCREASE OF DEEP CONVECTION NEAR THE LOW-LEVEL CIRCULATION CENTER. THEREFORE THE SYSTEM IS BEING NUMBERED AT THIS TIME. THERE IS PRONOUNCED UPPER-LEVEL OUTFLOW TO THE NORTH...EAST...AND SOUTH OF THE CENTER...BUT OUTFLOW IS LIMITED TO THE EAST. ANALYSES FROM THE UNIVERSITY OF WISCONSIN CIMSS INDICATE WEAK VERTICAL SHEAR ALONG THE PROJECTED PATH OF THE CYCLONE TO ABOUT 50W LONGITUDE. FARTHER WEST AND NORTH...THE SHEAR MAY INCREASE AS SUGGESTED BY THE LATEST 200 MB FORECAST FROM THE GFS MODEL. THEREFORE STRENGTHENING MAY BE INHIBITED LATE IN THE FORECAST PERIOD...ALTHOUGH THIS IS HIGHLY UNCERTAIN. INITIAL MOTION IS SLIGHTLY NORTH OF WEST AT AROUND 15 KT. DYNAMICAL MODEL PREDICTIONS INDICATE A WEAKENING OF THE MID-TROPOSPHERIC RIDGE TO THE NORTH OF THE TROPICAL CYCLONE OVER THE NEXT SEVERAL DAYS...DUE TO THE INCURSION OF A TROUGH INTO THE CENTRAL ATLANTIC. THIS TROUGH IS AT RATHER HIGH LATITUDES HOWEVER...SO IT IS NOT LIKELY TO PLAY A DIRECT ROLE IN STEERING THE TROPICAL CYCLONE. NOTWITHSTANDING...THE TRACK GUIDANCE GENERALLY SHOWS A SLOWING OF THE FORWARD SPEED AND A TURN TOWARD THE NORTHWEST LATER IN THE FORECAST PERIOD. THE NHC TRACK FORECAST FOLLOWS THIS SCENARIO...BUT IS A LITTLE TO THE SOUTH AND FASTER THAN MOST OF THE MODELS IN VIEW OF THE CURRENT MOTION WHICH SEEMS TO BE ACCELERATING TO THE WEST AS WE SPEAK. FORECASTER PASCH FORECAST POSITIONS AND MAX WINDS INITIAL 25/0300Z 11.2N 36.0W 25 KT 12HR VT 25/1200Z 11.8N 38.2W 35 KT 24HR VT 26/0000Z 12.4N 40.7W 40 KT 36HR VT 26/1200Z 13.0N 43.0W 45 KT 48HR VT 27/0000Z 13.8N 45.1W 50 KT 72HR VT 28/0000Z 16.0N 48.5W 60 KT 96HR VT 29/0000Z 18.0N 51.0W 70 KT 120HR VT 30/0000Z 20.0N 53.0W 70 KT |