000 WTNT41 KNHC 300259 TCDAT1 TROPICAL STORM KIRK DISCUSSION NUMBER 6 NWS NATIONAL HURRICANE CENTER MIAMI FL AL112012 1100 PM AST WED AUG 29 2012 THE SMALL CLOUD PATTERN ASSOCIATED WITH KIRK HAS BECOME BETTER ORGANIZED DURING THE LAST SEVERAL HOURS. DEEP CONVECTION HAS FULLY WRAPPED AROUND THE CENTER IN THE FORM OF A CENTRAL DENSE OVERCAST. AN EARLIER WINDSAT PASS SHOWED A CLOSED LOW-LEVEL RING OF CONVECTION...LIKELY PORTENDING AN INTENSIFICATION PHASE. DVORAK T-NUMBERS AT 0000 UTC WERE A CONSENSUS 3.0/45 KT. A 0056 UTC ASCAT PASS SHOWED SEVERAL RELIABLE 45 KT WIND VECTORS. SINCE THAT TIME...AN INTERMITTENT EYE HAS BEEN VISIBLE BUT THAT FEATURE HAS NOT PERSISTED. THE INITIAL INTENSITY ESTIMATE IS RAISED TO 50 KT BASED ON THE OVERALL INCREASE IN ORGANIZATION. A SERIES OF MORE RELIABLE FIXES HAS YIELDED A MORE CONFIDENT INITIAL MOTION OF 300/08. KIRK IS ALREADY ROUNDING THE WESTERN PERIPHERY OF A SUBTROPICAL RIDGE OVER THE EASTERN ATLANTIC...AND GLOBAL MODELS RESPOND BY SHOWING THE CYCLONE TURNING NORTHWESTWARD AND THEN NORTHWARD DURING THE NEXT DAY OR SO. A RAPIDLY ADVANCING SHORTWAVE TROUGH CURRENTLY OVER THE NORTHEASTERN UNITED STATES WILL SWEEP SOUTHEASTWARD AND ERODE THE RIDGE FURTHER IN ABOUT TWO DAYS... LEADING TO A RECURVATURE OF KIRK INTO THE WESTERLIES. A MORE COMPLEX SHORTWAVE TROUGH MOVING THROUGH THE CANADIAN MARITIME PROVINCES AROUND THAT TIME WILL CAUSE KIRK TO ACCELERATE FOR THE REMAINDER OF THE FORECAST. THE NEW NHC TRACK FORECAST IS SHIFTED A BIT TO THE RIGHT...AND IS IN GOOD AGREEMENT WITH THE GENERALLY RELIABLE GFS AND ECWMF MODEL SOLUTIONS. SOUTHWESTERLY SHEAR OVER KIRK APPEARS TO BE RELAXING AND IS EXPECTED TO REMAIN LOW FOR AT LEAST A COUPLE OF DAYS WHILE THE CYCLONE REMAINS OVER WARM WATERS. KIRK ALSO SEEMS TO BE AT LEAST PARTIALLY INSULATED FROM DRY AIR LURKING TO THE NORTHWEST. STRENGTHENING IS FORECAST UNTIL WESTERLY SHEAR INCREASES IN ABOUT 72 HOURS. THE INCREASE IN SHEAR ALONG WITH THE PASSAGE OF KIRK OF PROGRESSIVE LOWER SEA SURFACE TEMPERATURES SHOULD LEAD TO WEAKENING AROUND THAT TIME. GLOBAL MODELS SHOW A RAPIDLY ADVANCING FRONTAL BOUNDARY ENCROACHING ON KIRK IN 72-96 HOURS...AND THIS FEATURE IS FORECAST TO ABSORB THE CYCLONE IN ABOUT 96 HOURS. THE NHC INTENSITY FORECAST IS ADJUSTED UPWARD OVER THE PREVIOUS ONE BASED ON NOT ONLY SHORT- TERM TRENDS BUT ALSO THE LATEST GUIDANCE SHOWING A STRONGER SYSTEM. FORECAST POSITIONS AND MAX WINDS INIT 30/0300Z 25.9N 48.3W 50 KT 60 MPH 12H 30/1200Z 26.9N 49.4W 55 KT 65 MPH 24H 31/0000Z 28.6N 50.5W 60 KT 70 MPH 36H 31/1200Z 30.6N 50.8W 65 KT 75 MPH 48H 01/0000Z 33.3N 49.7W 70 KT 80 MPH 72H 02/0000Z 39.4N 43.7W 80 KT 90 MPH 96H 03/0000Z 47.1N 34.9W 70 KT 80 MPH 120H 04/0000Z...DISSIPATED $$ FORECASTER KIMBERLAIN