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| #150688 (Received by flhurricane at: 4:37 PM 13.Sep.2007) TCDAT3 TROPICAL DEPRESSION EIGHT DISCUSSION NUMBER 6 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL082007 500 PM EDT THU SEP 13 2007 CONVENTIONAL SATELLITE IMAGERY INDICATES A SMALLER WEAKER LOW ROTATING ABOUT A MORE DOMINANT...BROAD...CIRCULATION TO THE SOUTHEAST. THE INITIAL POSITION WILL BE BASED ON A CENTROID POSITION OF THE TWO CIRCULATION CENTERS. THERE ARE NO CHANGES TO THE DVORAK SATELLITE INTENSITY ESTIMATES FROM THIS MORNING...AND THE INITIAL INTENSITY REMAINS AS 30 KT. THE OFFICIAL FORECAST INTENSITY REMAINS VIRTUALLY UNCHANGED FROM THE PREVIOUS FORECAST...SUGGESTING A POSSIBILITY OF STRENGTHENING TO A TROPICAL STORM DURING THE NEXT 12 HOURS. AFTERWARD...THE INTENSITY MODELS INDICATE VERY LITTLE STRENGTHENING THROUGH THE 72 HOUR PERIOD...WITH A WEAKENING THROUGH THE REMAINDER OF THE PERIOD AS UPPER LEVEL WESTERLIES ARE EXPECTED TO SPREAD FROM THE EASTERN CARIBBEAN OVER THE ADJACENT ATLANTIC WATERS. INITIAL MOTION IS ESTIMATED AT 290/5...A LITTLE TO THE RIGHT OF THE PREVIOUS PACKAGE. THE CYCLONE SHOULD GRADUALLY CONTINUE ON A GENERAL WEST-NORTHWESTWARD MOTION WITHIN WEAK STEERING FLOW OF A MID- TROPOSPHERIC RIDGE TO THE NORTH THROUGH THE FORECAST PERIOD. THE DYNAMICAL MODELS ARE IN MORE AGREEMENT THAN THIS MORNING...WITH THE 12Z ECMWF NOW SUGGESTING A MOTION SIMILAR TO THE OTHER MODELS. THE NOGAPS...HOWEVER...SHOWS THE MOST VERTICAL DEPTH WHICH APPEARS TO BE INFLUENCING A DRAMATIC TURN TO THE RIGHT TOWARD A RETROGRADING UPPER LEVEL TROUGH SITUATED TO THE NORTHEAST OF THE DEPRESSION. THE OFFICIAL FORECAST IS SIMILAR TO THE PREVIOUS FORECAST...WITH A SLIGHT ADJUSTMENT TO THE RIGHT...AND AGREES WITH A BLEND OF ALL THE AVAILABLE DYNAMICAL GUIDANCE WITH THE EXCEPTION OF THE NOGAPS. FORECAST POSITIONS AND MAX WINDS INITIAL 13/2100Z 14.2N 48.4W 30 KT 12HR VT 14/0600Z 14.5N 49.2W 35 KT 24HR VT 14/1800Z 15.0N 50.2W 35 KT 36HR VT 15/0600Z 15.5N 51.4W 35 KT 48HR VT 15/1800Z 15.9N 52.5W 40 KT 72HR VT 16/1800Z 17.0N 55.4W 40 KT 96HR VT 17/1800Z 18.0N 58.0W 35 KT 120HR VT 18/1800Z 19.1N 60.5W 30 KT $$ FORECASTER ROBERTS/BEVEN |
