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#297817 (Received by flhurricane at: 4:37 PM 25.Sep.2009) TCDAT3 TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082009 500 PM AST FRI SEP 25 2009 SATELLITE IMAGERY INDICATES THAT THE TROPICAL WAVE OVER THE EASTERN ATLANTIC HAS DEVELOPED SUFFICIENT CONVECTION AND CIRCULATION TO BE DESIGNATED A TROPICAL DEPRESSION. SATELLITE INTENSITY ESTIMATES BASED ON BANDING IN THE NORTHERN SEMICIRCLE ARE 30 KT FROM TAFB AND 25 KT FROM SAB. THE INITIAL INTENSITY IS SET TO 30 KT. THE CIRRUS OUTFLOW IS FAIR TO GOOD IN THE NORTHERN SEMICIRCLE AND RESTRICTED ELSEWHERE. THE DEPRESSION IS CURRENTLY EXPERIENCING 10-15 KT OF SOUTHWESTERLY VERTICAL WIND SHEAR. THE SHEAR IS FORECAST TO INCREASE AFTER 12 HR OR SO...WITH THE FORECAST TRACK LIKELY TAKING THE CYCLONE NEAR AN UPPER-LEVEL TROUGH BY 48 HR. THIS...COMBINED WITH A TONGUE OF COOLER SEA SURFACE TEMPERATURES ALONG THE FORECAST TRACK...SUGGEST THAT THE SYSTEM WILL ONLY HAVE A SMALL CHANCE TO STRENGTHEN BEFORE ENCOUNTERING CONDITIONS THAT SHOULD CAUSE DISSIPATION. THE INTENSITY FORECAST CALLS FOR SLIGHT STRENGTHENING DURING THE FIRST 12 HR...FOLLOWED BY GRADUAL WEAKENING. THE SYSTEM IS FORECAST TO BECOME A REMNANT LOW BY 72 HR AND DISSIPATE COMPLETELY BY 96 HR. THE INITIAL MOTION IS 305/12. THE CYCLONE IS FORECAST TO CONTINUE THIS GENERAL MOTION TOWARD AN UPPER-LEVEL TROUGH AND AN ASSOCIATED WEAKNESS IN THE LOW/MID-LEVEL SUBTROPICAL RIDGE FOR THE NEXT 36 HR OR SO...THEN TURN NORTHWARD INTO THE WEAKNESS BEFORE DISSIPATION. FORECAST POSITIONS AND MAX WINDS INITIAL 25/2100Z 16.4N 31.6W 30 KT 12HR VT 26/0600Z 17.3N 33.1W 35 KT 24HR VT 26/1800Z 18.4N 35.0W 35 KT 36HR VT 27/0600Z 19.8N 36.8W 30 KT 48HR VT 27/1800Z 21.4N 38.1W 25 KT 72HR VT 28/1800Z 24.0N 39.5W 20 KT...REMNANT LOW 96HR VT 29/1800Z...DISSIPATED $$ FORECASTER BEVEN |