000 WTNT43 KNHC 292157 TCDAT3 HURRICANE SANDY DISCUSSION NUMBER 30...CORRECTED NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012 500 PM EDT MON OCT 29 2012 THE CONVECTIVE STRUCTURE OF SANDY HAS DETERIORATED TODAY...EVEN AS THE CENTRAL PRESSURE HAS CONTINUED TO SLOWLY FALL...SUGGESTING THAT THE CONVECTION IS NO LONGER DRIVING THE BUS. THE INTENSIFICATION OBSERVED THIS MORNING WAS ASSOCIATED WITH STRONG WINDS OCCURRING TO THE SOUTHWEST OF THE CENTER...OUTSIDE OF THE CENTRAL CORE...AND WAS ALMOST CERTAINLY DUE TO BAROCLINIC FORCING. IN ADDITION...AIRCRAFT DATA INDICATE THAT THERE ARE STRONG TEMPERATURE CONTRASTS VERY NEAR A MODEST RESIDUAL WARM CORE. WATER VAPOR IMAGERY INDICATES THAT SANDY IS BECOMING ABSORBED WITHIN A LARGE MID-LATITUDE CYCLONIC CIRCULATION. ALL OF THESE CONSIDERATIONS LEAD US TO CONCLUDE THAT THE MOST APPROPRIATE CLASSIFICATION AT ADVISORY TIME IS EXTRATROPICAL. HOWEVER...FOR CONTINUITY OF SERVICE NHC WILL CONTINUE TO ISSUE ADVISORIES THROUGH LANDFALL. A POST-STORM ANALYSIS WILL RE-EXAMINE THE TIMING OF EXTRATROPICAL TRANSITION. WE ANTICIPATES THAT THE LAST NHC ADVISORY ON SANDY WILL BE ISSUED AT 11 PM EDT TONIGHT. SINCE ALL COASTAL TROPICAL CYCLONE WARNINGS HAVE BEEN DISCONTINUED...THERE WILL BE NO INTERMEDIATE PUBLIC ADVISORIES ISSUED BETWEEN NOW AND THE 11 PM NHC ADVISORY. TO PROVIDE A CONTINUOUS FLOW OF INFORMATION...NHC WILL ISSUE TROPICAL CYCLONE UPDATES AT 7 PM AND 9 PM EDT...AND AT THE TIME OF LANDFALL. THESE UPDATES ARE ISSUED UNDER WMO HEADER WTNT63...AND AWIPS HEADER TCUAT3...AND WILL ALSO BE AVAILABLE ON THE NHC WEBSITE. BEGINNING AT 5 AM EDT TUESDAY...PUBLIC ADVISORIES WILL BE ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER...HPC...UNDER THE SAME WMO AND AWIPS HEADERS AS THE NHC PUBLIC ADVISORIES...WHICH WILL ALSO BE AVAILABLE VIA THE NHC WEBSITE. THERE HAS BEEN NO SIGNIFICANT CHANGE TO THE POST-LANDFALL TRACK OR INTENSITY FORECAST. DESPITE THE RAPID FORWARD MOTION TODAY...SANDY IS EXPECTED TO STALL INLAND TOMORROW. THIS...COUPLED WITH THE VERY LARGE SIZE OF THE SYSTEM...WILL MEAN THAT CONDITIONS WILL BE SLOW TO IMPROVE IN THE AFFECTED AREAS. STRONG WINDS WILL PERSIST ALONG THE COAST AND SPREAD FARTHER INLAND THROUGH AT LEAST TUESDAY. OF PARTICULAR CONCERN ARE THE UPPER FLOORS OF HIGH-RISE BUILDINGS...AS RECONNAISSANCE DATA INDICATE THAT WINDS JUST A FEW HUNDRED FEET IN ALTITUDE ARE VERY MUCH STRONGER THAN THOSE NEAR THE SURFACE. EVEN AS SANDY WEAKENS...HEAVY RAINS WILL PERSIST OVER A LARGE AREA...POSING A VERY SIGNIFICANT INLAND FLOOD RISK. TO AVOID A HIGHLY DISRUPTIVE CHANGE FROM TROPICAL TO NON-TROPICAL WARNINGS AS SANDY BECOMES POST-TROPICAL...THE WIND AND OTHER HAZARDS WILL CONTINUE TO BE CONVEYED THROUGH HIGH WIND WARNINGS ISSUED BY LOCAL NATIONAL WEATHER SERVICE OFFICES. FORECAST POSITIONS AND MAX WINDS INIT 29/2100Z 38.8N 74.4W 80 KT 90 MPH 12H 30/0600Z 39.8N 76.6W 65 KT 75 MPH...POST-TROP/EXTRATROP 24H 30/1800Z 40.4N 78.3W 50 KT 60 MPH...POST-TROP/EXTRATROP 36H 31/0600Z 41.3N 78.2W 40 KT 45 MPH...POST-TROP/EXTRATROP 48H 31/1800Z 42.8N 77.5W 30 KT 35 MPH...POST-TROP/EXTRATROP 72H 01/1800Z 45.1N 75.5W 30 KT 35 MPH...POST-TROP/EXTRATROP 96H 02/1800Z 46.3N 72.2W 25 KT 30 MPH...POST-TROP/EXTRATROP 120H 03/1800Z 47.5N 65.5W 20 KT 25 MPH...POST-TROP/EXTRATROP $$ FORECASTER KNABB/FRANKLIN