000 WTNT44 KNHC 252037 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 53 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 500 PM AST TUE SEP 25 2012 A BAND OF CONVECTION THAT HAS DEVELOPED DURING THE PAST FEW HOURS HAS WRAPPED AROUND ALL BUT THE SOUTHEAST QUADRANT OF THE EYE-LIKE FEATURE SEEN IN INFRARED SATELLITE IMAGERY. A DVORAK DATA T-NUMBER OF 3.0 FROM SAB AND RECENT RAW T-NUMBERS FROM UW/CIMSS ADT SUGGEST THAT NADINE COULD BE A LITTLE STRONGER...BUT FOR NOW I PREFER TO KEEP THE INTENSITY AT 40 KT TO SEE IF THE CONVECTION CAN PERSIST. NADINE APPEARS TO HAVE HESITATED FOR A TIME EARLIER TODAY...BUT THE LONGER TERM MOTION ESTIMATE IS WEST-SOUTHWESTWARD AT 4 KT. THERE HAS BEEN NO CHANGE TO THE TRACK FORECAST REASONING SINCE THIS MORNING. NADINE SHOULD TURN SOUTHWARD VERY SOON AS NORTHERLY MID-LEVEL FLOW INCREASES BETWEEN A STRONG RIDGE OVER THE CENTRAL ATLANTIC AND A DEEPENING TROUGH OVER THE EASTERN ATLANTIC. IN A COUPLE OF DAYS...THE STORM IS FORECAST TO TURN WESTWARD...THEN NORTHWESTWARD AFTER 72 HOURS AS THE RIDGE SLIDES EASTWARD. THE TRACK GUIDANCE HAS SHIFTED SOMEWHAT WESTWARD NEAR THE END OF THE PERIOD...BUT OUT OF RESPECT FOR THE MORE EASTERN GFS AND THE PREVIOUS NHC FORECAST...THE NEW TRACK HAS NOT BEEN ADJUSTED VERY FAR. EXCEPT FOR SOME DRY AIR THAT NADINE COULD INGEST DURING THE NEXT COUPLE OF DAYS...CONDITIONS ARE EXPECTED TO BECOME A LITTLE MORE FAVORABLE FOR STRENGTHENING AS THE SYSTEM MOVES OVER SLIGHTLY WARMER SSTS AND VERTICAL SHEAR REMAINS LOW. THE NHC FORECAST CALLS FOR GRADUAL STRENGTHENING DURING THE NEXT 48 HOURS AND IS IN LINE WITH THE LATEST SHIPS/LGEM GUIDANCE. AFTER 72 HOURS...INCREASING SOUTHWESTERLY SHEAR AND COOLER WATER SHOULD CAUSE NADINE TO WEAKEN. HOWEVER...THE LONG-RANGE GLOBAL MODEL MODELS SUGGEST THAT THE ALREADY TWO-WEEK-OLD CYCLONE IS LIKELY TO REMAIN OVER THE EAST-CENTRAL ATLANTIC FOR A RATHER EXTENDED PERIOD OF TIME. FORECAST POSITIONS AND MAX WINDS INIT 25/2100Z 31.7N 30.4W 40 KT 45 MPH 12H 26/0600Z 31.1N 30.6W 45 KT 50 MPH 24H 26/1800Z 30.2N 30.7W 45 KT 50 MPH 36H 27/0600Z 29.3N 31.1W 50 KT 60 MPH 48H 27/1800Z 28.8N 32.0W 55 KT 65 MPH 72H 28/1800Z 29.2N 33.4W 55 KT 65 MPH 96H 29/1800Z 31.0N 35.0W 50 KT 60 MPH 120H 30/1800Z 33.5N 35.8W 45 KT 50 MPH $$ FORECASTER BROWN