Official Discussion issued by the National Hurricane Center
SIX (AL062010) DATA RELEASED: 8/21/2010 9:00:00 PM UTC
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Copy of official data TROPICAL DEPRESSION SIX DISCUSSION NUMBER 1 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 500 PM EDT SAT AUG 21 2010 SATELLITE IMAGES INDICATE THAT THE AREA OF LOW PRESSURE SOUTHWEST OF THE CAPE VERDE ISLANDS HAS BECOME CONSIDERABLY BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. THE LOW APPEARS TO HAVE BECOME MORE SEPARATED FROM THE LARGE AREA OF SOUTHWESTERLY FLOW WHICH HAS BEEN PRESENT OVER THE TROPICAL ATLANTIC FOR THE PAST SEVERAL DAYS....THOUGH IT IS STILL A BIT ELONGATED TO THE NORTHEAST. A LONG CURVED BAND OF CONVECTION ALSO WRAPS AROUND THE SOUTHERN AND WESTERN SEMICIRCLE. THE INITIAL INTENSITY WILL BE 25 KT...WHICH AGREES WITH DVORAK CLASSIFICATIONS FROM TAFB/SAB OF T1.5...25 KT...AND A 25 KT ASCAT PASS FROM THIS MORNING. A LARGE UPPER-LEVEL ANTICYCLONE IS FORECAST TO BE NEAR THE DEPRESSION...WHICH SHOULD CAUSE ONLY WEAK TO MODERATE NORTHEASTERLY SHEAR FOR THE NEXT SEVERAL DAYS. COMBINED WITH WARM SSTS...AT LEAST STEADY STRENGTHENING IS EXPECTED UNTIL THE END OF THE FORECAST PERIOD. BY THAT TIME...SOME INCREASE IN SOUTHWESTERLY SHEAR IS POSSIBLE AS THE CYCLONE APPROACHES THE MID-OCEANIC TROUGH. THE INTENSITY GUIDANCE IS IN RELATIVELY GOOD AGREEMENT FOR SUCH A WEAK SYSTEM WITH ALL RELIABLE GUIDANCE MAKING THE DEPRESSION A HURRICANE WITHIN A FEW DAYS. THE NHC FORECAST IS CLOSE TO THE SHIPS/LGEM MODELS...SHOWING A LARGE POWERFUL HURRICANE OVER THE CENTRAL ATLANTIC OCEAN IN A FEW DAYS. THE INITIAL MOTION ESTIMATE IS 285/7. A WEST-NORTHWEST MOTION WITH INCREASING FORWARD SPEED IS EXPECTED AS THE DEPRESSION LEAVES THE STRONG WESTERLY LOW-LEVEL FLOW ENVIRONMENT OF THE TROPICAL ATLANTIC AND BECOMES STEERED BY A RIDGE OVER THE CENTRAL ATLANTIC OCEAN. MOST OF THE MODELS SHOW THE CYCLONE TURNING TOWARD THE NORTHWEST DUE TO A WEAKNESS IN THE RIDGE ALONG 50W IN ABOUT 3 DAYS. MODEL GUIDANCE IS |