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#538676 (Received by flhurricane at: 10:38 AM 30.Aug.2012) TCDAT2 TROPICAL DEPRESSION TWELVE DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL122012 1100 AM EDT THU AUG 30 2012 SATELLITE IMAGES INDICATE THAT THE AREA OF THE LOW PRESSURE OVER THE CENTRAL TROPICAL ATLANTIC HAS DEVELOPED ENOUGH ORGANIZATION TO BE CONSIDERED A TROPICAL DEPRESSION. A WELL-DEFINED CURVED BAND IS ON THE WESTERN SIDE OF THE CIRCULATION...AND THE CENTER APPEARS TO BE EMBEDDED ON THE EASTERN SIDE OF THE BAND. THE ADVISORY INTENSITY IS 30 KT...WHICH IS BASED ON A BLEND OF TAFB AND SAB 1200 UTC ESTIMATES... THOUGH IT MIGHT BE A LITTLE STRONGER BASED ON THE LATEST PICTURES. AS THE DEPRESSION MOVES OVER WARM WATERS DURING THE NEXT FEW DAYS...FURTHER STRENGTHENING SEEMS LIKELY WHILE AN UPPER-LEVEL ANTICYCLONE BUILDS NEAR THE SYSTEM. THE LONG RANGE INTENSITY SEEMS RATHER UNCERTAIN AS THE GLOBAL MODELS SHOW WILDLY DIFFERENT SYNOPTIC PATTERNS. THE NHC WIND SPEED FORECAST IS CLOSE TO THE INTENSITY CONSENSUS...AND COULD BE CONSERVATIVE IF THE LOW SHEAR ENVIRONMENT SHOWN BY THE GFS MATERIALIZES. THE INITIAL MOTION IS ABOUT 275/17. MODEL GUIDANCE SUGGESTS THE DEPRESSION WILL TURN TOWARD THE WEST-NORTHWEST SOON AS IT MOVES TOWARD A WEAKNESS IN THE SUBTROPICAL RIDGE...PARTIALLY RELATED TO KIRK. WHILE THE RIDGE IS EXPECTED TO REBUILD SOMEWHAT AS KIRK MOVES OUT TO SEA...ALL OF THE GLOBAL MODELS SHOW TROUGHING BETWEEN 60W-70W IN THE MEDIUM RANGE PERIOD...WHICH WILL PROBABLY TURN THE CYCLONE TO THE NORTHWEST AND NORTH. THERE IS A LOT OF UNCERTAINTY IN THE LONG RANGE RELATED TO WHETHER THE SYSTEM RECURVES AHEAD OF THE TROUGH OR GETS TRAPPED BENEATH A REBUILDING RIDGE. THE NHC FORECAST IS A BIT FASTER AND WEST OF THE CONSENSUS THROUGHOUT THE PERIOD...BUT THIS FORECAST STILL KEEPS THE CYCLONE WELL TO THE NORTHEAST OF THE LESSER ANTILLES. FORECAST POSITIONS AND MAX WINDS INIT 30/1500Z 14.1N 43.4W 30 KT 35 MPH 12H 31/0000Z 14.8N 45.8W 40 KT 45 MPH 24H 31/1200Z 15.9N 48.9W 45 KT 50 MPH 36H 01/0000Z 17.1N 52.1W 55 KT 65 MPH 48H 01/1200Z 18.5N 55.0W 65 KT 75 MPH 72H 02/1200Z 21.0N 59.0W 80 KT 90 MPH 96H 03/1200Z 24.5N 61.0W 80 KT 90 MPH 120H 04/1200Z 27.0N 61.0W 80 KT 90 MPH $$ FORECASTER BLAKE |