000 WTNT44 KNHC 231454 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 44 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 1100 AM AST SUN SEP 23 2012 DEEP CONVECTION ASSOCIATED WITH POST-TROPICAL CYCLONE NADINE HAS INCREASED SIGNIFICANTLY DURING THE PAST 12-18 HOURS. ALTHOUGH THE THUNDERSTORM ACTIVITY NEAR THE CENTER HAS THINNED A BIT THIS MORNING...THE LOW HAS MAINTAINED DEEP CONVECTION SINCE YESTERDAY AFTERNOON. THERE HAS ALSO BEEN AN INCREASE IN ORGANIZATION OF THE THUNDERSTORM ACTIVITY AS THE PRIMARY BAND NOW WRAPS ABOUT HALF WAY AROUND THE CIRCULATION. BASED ON THE IMPROVED SATELLITE APPEARANCE AND TROPICAL CLASSIFICATIONS OF 2.5 AND 3.0 FROM SAB AND TAFB... NADINE IS CLASSIFIED AS A TROPICAL STORM ONCE AGAIN. DROPSONDE DATA FROM AN ONGOING NASA GLOBAL HAWK MISSION SUGGESTS THAT THE MAXIMUM WINDS ARE NEAR 50 KT. A DROPWINDSONDE NEAR THE CENTER AROUND 1030 UTC MEASURED A PRESSURE OF 989.9 MB WITH STRONG WINDS...SO THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 986 MB. NADINE DRIFTED EASTWARD OVERNIGHT...BUT A SLOW WESTWARD MOTION APPEARS TO HAVE STARTED. UNLIKE SEVERAL DAYS AGO...THE TRACK MODEL GUIDANCE IS IN RELATIVELY GOOD AGREEMENT. THE GLOBAL MODELS INDICATE THAT NADINE WILL MOVE GENERALLY WESTWARD DURING THE NEXT SEVERAL DAYS AROUND THE SOUTHEASTERN SIDE OF A DEEP-LAYER RIDGE OVER THE CENTRAL ATLANTIC. THE RIDGE IS FORECAST TO SLIDE EASTWARD NEAR THE END OF THE FORECAST PERIOD AS A MID-LATITUDE TROUGH MOVES INTO THE WESTERN ATLANTIC. THIS SHOULD CAUSE NADINE TO TURN NORTHWESTWARD LATE IN THE PERIOD. THE NHC TRACK FORECAST IS IN GOOD AGREEMENT WITH THE GUIDANCE AND NEAR THE MULTI-MODEL CONSENSUS. NADINE IS CURRENTLY OVER SSTS OF AROUND 26 DEGREES CELSIUS AND IN MODERATE SOUTHWESTERLY SHEAR. THESE CONDITIONS ARE EXPECTED TO REMAIN UNCHANGED FOR THE NEXT 24 TO 36 HOURS...SO LITTLE CHANGE IN STRENGTH IS ANTICIPATED DURING THAT TIME. IN A COUPLE OF DAYS...THE SHEAR IS FORECAST TO DECREASE AND NADINE SHOULD BE MOVING OVER SLIGHTLY WARMER WATER BY THEN. AS A RESULT...GRADUAL STRENGTHENING IS INDICATED BY 48 HOURS. THE NHC INTENSITY FORECAST SHOWS NADINE ATTAINING HURRICANE IN A FEW DAYS...AND THIS IS SUPPORTED BY BOTH THE SHIPS AND LGEM MODELS. FORECAST POSITIONS AND MAX WINDS INIT 23/1500Z 30.6N 25.6W 50 KT 60 MPH 12H 24/0000Z 30.7N 26.2W 50 KT 60 MPH 24H 24/1200Z 31.0N 27.4W 55 KT 65 MPH 36H 25/0000Z 31.4N 28.8W 55 KT 65 MPH 48H 25/1200Z 31.5N 30.1W 60 KT 70 MPH 72H 26/1200Z 30.9N 31.8W 65 KT 75 MPH 96H 27/1200Z 30.5N 33.5W 70 KT 80 MPH 120H 28/1200Z 32.5N 36.0W 70 KT 80 MPH $$ FORECASTER BROWN