000 WTNT44 KNHC 191452 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 33 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 1100 AM AST WED SEP 19 2012 DEEP CONVECTION HAS BEEN GRADUALLY DECLINING AND IS BECOMING FARTHER REMOVED FROM THE CENTER. AMSU DATA SHOWED A MID- TO UPPER-LEVEL WARM CORE STRUCTURE...BUT THE LACK OF CENTRAL CONVECTION IS INDICATIVE OF A DECAYING TROPICAL CYCLONE. DVORAK INTENSITY ESTIMATES ARE 35 KT BUT SINCE THIS IS SUCH A MARGINAL TROPICAL CYCLONE...THESE ESTIMATES MAY BE PROBLEMATIC. A RECENT ASCAT PASS SHOWED THAT THE SYSTEM STILL HAD WINDS TO 45 KT. HOWEVER...IF THE CURRENT CONVECTIVE TREND CONTINUES...NADINE WILL SOON NO LONGER QUALIFY AS A TROPICAL OR SUBTROPICAL CYCLONE. THE OFFICIAL FORECAST SHOWS THE SYSTEM BECOMING POST-TROPICAL IN 24 HOURS BUT THIS TRANSITION COULD OCCUR EVEN EARLIER THAN THAT. THE INTENSITY FORECAST MAINTAINS THE 45-KT INTENSITY FOR THE NEXT SEVERAL DAYS SINCE THE POST-TROPICAL CYCLONE WILL PROBABLY FIND SOME SOURCES OF BAROCLINIC ENERGY DURING THE FORECAST PERIOD. THE MOTION IS BECOMING ERRATIC AND THE CURRENT ESTIMATE IS 020/04. MOST OF THE BETTER-PERFORMING DYNAMICAL MODELS ARE IN GOOD AGREEMENT THAT THE SYSTEM SHOULD SOON TURN TOWARD THE EAST-SOUTHEAST AS IT BECOMES CAUGHT IN THE STEERING FLOW ON THE SOUTHWEST SIDE OF A STRONG MID-TROPOSPHERIC TROUGH AND CUTOFF LOW OVER THE EASTERN ATLANTIC DURING THE NEXT 48 HOURS OR SO. IN THE LATTER PART OF THE FORECAST PERIOD...THE MODELS BECOME MORE DIVERGENT WITH THE U.K. MET. OFFICE MODEL TAKING THE SYSTEM SOUTHWARD AND WESTWARD...THE ECMWF SHOWING THE CYCLONE BECOMING ABSORBED...AND THE GFS MOVING THE SYSTEM QUICKLY TOWARD PORTUGAL. AS A COMPROMISE...THE OFFICIAL FORECAST MOVES THE CYCLONE SLOWLY EASTWARD FROM DAYS 3 TO 5. THIS IS SIMILAR TO THE PREVIOUS NHC TRACK AND NOT FAR FROM THE DYNAMICAL MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 19/1500Z 37.2N 31.8W 45 KT 50 MPH 12H 20/0000Z 37.4N 31.4W 45 KT 50 MPH 24H 20/1200Z 36.6N 30.2W 45 KT 50 MPH...POST-TROPICAL 36H 21/0000Z 35.5N 28.4W 45 KT 50 MPH...POST-TROPICAL 48H 21/1200Z 34.5N 26.5W 45 KT 50 MPH...POST-TROPICAL 72H 22/1200Z 34.5N 23.5W 45 KT 50 MPH...POST-TROPICAL 96H 23/1200Z 34.5N 22.0W 45 KT 50 MPH...POST-TROPICAL 120H 24/1200Z 34.5N 21.0W 45 KT 50 MPH...POST-TROPICAL $$ FORECASTER PASCH/ZELINSKY