000 WTNT44 KNHC 040255 TCDAT4 TROPICAL STORM NADINE DISCUSSION NUMBER 86 NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012 1100 PM AST WED OCT 03 2012 NADINE IS A VERTICALLY SHALLOW TROPICAL CYCLONE THAT IS CURRENTLY SITUATED IN THE WARM SECTOR OF AN EXTREMELY LARGE OCCLUDED EXTRATROPICAL LOW PRESSURE SYSTEM. ALTHOUGH NADINE IS NOT A CLASSICAL TROPICAL CYCLONE...RECENT SSMIS AND AMSU MICROWAVE IMAGERY INDICATE THAT A LARGE AND WELL-PRONOUNCED BAND OF SHALLOW TO MODERATE CONVECTION EXISTS IN THE EASTERN SEMICIRCLE...DESPITE THE RATHER DEGRADED AND POOR APPEARANCE IN GEOSTATIONARY INFRARED SATELLITE IMAGERY. THE INITIAL INTENSITY OF 40 KT IS BEING MAINTAINED FROM THE PREVIOUS ADVISORY BASED ON A DVORAK SATELLITE INTENSITY CI-NUMBER OF T2.5/35 KT FROM TAFB AND A 36-KT WIND REPORT FROM SHIP BATFR18 LOCATED IN THE SOUTHEASTERN QUADRANT AT 0200 UTC. THE MOTION ESTIMATE IS 035/21 KT. NADINE REMAINS EMBEDDED WITHIN THE FLOW ON THE EAST SIDE OF A MUCH LARGER DEEP-LAYER EXTRATROPICAL CYCLONE. THE CURRENT NORTHEASTWARD MOTION ACCOMPANIED BY A GRADUAL INCREASE IN FORWARD SPEED IS EXPECTED OVER THE NEXT 12 HOURS OR SO...FOLLOWED BY A TURN TO THE NORTH BY THURSDAY AFTERNOON. IN 48 TO 72 HOURS...THEN POST-TROPICAL/EXTRATROPICAL NADINE IS FORECAST TO TURN NORTHWESTWARD AND BECOME ABSORBED INTO THE LARGER LOW IN WHICH IT IS CURRENTLY EMBEDDED. THE NHC OFFICIAL TRACK FORECAST IS SIMILAR TO THE PREVIOUS ADVISORY..AND CLOSELY FOLLOWS THE TREND OF THE CONSENSUS MODELS TV15 AND TVCA. THE 36-KT SHIP REPORT AND A FASTER FORWARD SPEED IN EXCESS OF 20 KT ARGUES FOR KEEPING THE INTENSITY AT 40 KT FROM NOW THROUGH LANDFALL IN THE AZORES. NADINE COULD MERGE WITH EITHER A COLD FRONT APPROACHING FROM THE WEST OR CATCH UP TO AND MERGE WITH A WARM FRONT LOCATED JUST SOUTH OF THE AZORES...WHICH WOULD RESULT IN EXTRATROPICAL TRANSITION SOONER THAN CURRENTLY FORECAST. BUT BY 24 HOURS...CLEAR EXTRATROPICAL TRANSITION IS LIKELY. REGARDLESS OF THE STATUS OF NADINE...THE CYCLONE IS EXPECTED TO PRODUCE TROPICAL-STORM- OR GALE-FORCE WINDS IT PASSES THROUGH THE AZORES LATER TONIGHT AND THURSDAY MORNING. THE 34-KT WIND RADII WERE EXPANDED IN THE EASTERN SEMICIRCLE BASED ON SEVERAL OBSERVATIONS OVER THE PAST 6 HOURS FROM SHIPS WITH CALL SIGNS BATFR13...BATFR15...AND BATFR18...WHICH HAVE BEEN NAVIGATING THROUGH THE SOUTHEASTERN QUADRANT OF THE CIRCULATION OF NADINE. FORECAST POSITIONS AND MAX WINDS INIT 04/0300Z 37.4N 30.3W 40 KT 45 MPH 12H 04/1200Z 40.2N 28.1W 35 KT 40 MPH...POST-TROPICAL 24H 05/0000Z 44.5N 26.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 36H 05/1200Z 47.0N 26.5W 35 KT 40 MPH...POST-TROP/EXTRATROP 48H 06/0000Z 49.0N 27.0W 35 KT 40 MPH...POST-TROP/EXTRATROP 72H 07/0000Z...ABSORBED BY LARGER EXTRATROPICAL CYCLONE $$ FORECASTER STEWART