000 WTNT41 KNHC 220243 TCDAT1 TROPICAL DEPRESSION SIX DISCUSSION NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL AL062010 1100 PM AST SAT AUG 21 2010 CONVENTIONAL SATELLITE AND A 2202 UTC SSMIS MICROWAVE OVERPASS SHOW IMPROVED CURVED BANDING...PARTICULARLY OVER THE WESTERN PORTION OF THE CYCLONE. ALTHOUGH DEEP CONVECTION REMAINS A BIT LIMITED OVER THE EASTERN SEMI-CIRCLE...A 2300 UTC ASCAT PASS INDICATED A MORE SYMMETRIC CIRCULATION THAN EARLIER NOTED...AND BELIEVABLE 25 KT WINDS OVER THE SOUTHEAST QUADRANT. OUTFLOW OVER THE NORTHWESTERN AREA OF THE SYSTEM APPEARS TO BE IMPROVING AND HAS BECOME MORE DIFFLUENT. SATELLITE INTENSITY ESTIMATES FROM TAFB AND SAB ARE 2.0 AND 1.5 RESPECTIVELY. BASED ON THE PREMISE THAT THE WINDS ARE PROBABLY A LITTLE STRONGER IN THE CONVECTIVE BANDING TO THE WEST AND NORTHWEST OF THE CENTER...THE INITIAL INTENSITY IS ADJUSTED UP TO 30 KT. THE CYCLONE SHOULD GRADUALLY STRENGTHEN AS IT REMAINS OVER WARM SEA SURFACE TEMPERATURES AND WITHIN A RELATIVELY LOW NORTHEASTERLY SHEAR ENVIRONMENT DURING...AT LEAST FOR THE NEXT 3 DAYS. THE SHIPS AND THE GFDL CONTINUE TO INDICATE THAT THE SYSTEM WILL BECOME A HURRICANE WITHIN 3 DAYS...AND THIS IS ALSO INDICATED IN THE OFFICIAL FORECAST. THROUGH THE REMAINING PERIOD...INCREASING SOUTHWESTERLY SHEAR IS EXPECTED OVER THE TRACK IN RESPONSE TO A MID TO UPPER TROUGH MOVING OFF OF THE EASTERN SEABOARD AROUND DAY 5. SUBSEQUENTLY...THE INTENSITY FORECAST INDICATES ONLY MODEST STRENGTHENING DURING THIS TIME-FRAME. THE SYSTEM HAS BEEN MOVING WEST-NORTHWESTWARD...OR...290/7. THE DEEP TRADES ASSOCIATED WITH THE SUBTROPICAL RIDGE TO THE NORTH OF THE DEPRESSION NOW APPEAR TO BE THE MORE DOMINANT STEERING MECHANISM...WITH LESS OF AN INFLUENCE FROM THE SOUTHWESTERLY MONSOONAL FLOW. DYNAMICAL MODELS ARE IN GOOD AGREEMENT WITH THE RIDGE STEERING THE CYCLONE IN A WEST-NORTHWESTWARD MOTION THROUGH DAY 3. AFTERWARD...A TURN TOWARD THE NORTHWEST IS INDICATED IN THE OFFICIAL FORECAST AS A DEEP-LAYER MID-LATITUDE TROUGH MOVES OVER THE CENTRAL ATLANTIC AND BREAKS DOWN THE WESTERN PERIPHERY OF THE RIDGE. THE NHC TRACK FORECAST IS A LITTLE SLOWER THAN THE PREVIOUS ADVISORY...AND IS BASED ON THE MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INITIAL 22/0300Z 11.3N 32.6W 30 KT 12HR VT 22/1200Z 12.0N 33.9W 35 KT 24HR VT 23/0000Z 12.9N 36.0W 40 KT 36HR VT 23/1200Z 13.8N 38.4W 50 KT 48HR VT 24/0000Z 14.7N 41.3W 60 KT 72HR VT 25/0000Z 18.0N 47.0W 80 KT 96HR VT 26/0000Z 21.5N 51.5W 90 KT 120HR VT 27/0000Z 25.0N 55.0W 95 KT $$ FORECASTER ROBERTS/BEVEN