000 WTNT43 KNHC 280842 TCDAT3 HURRICANE SANDY DISCUSSION NUMBER 24 NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012 500 AM EDT SUN OCT 28 2012 THE MOST RECENT AIR FORCE HURRICANE HUNTER AIRCRAFT MISSION DID NOT FIND WINDS OF HURRICANE FORCE NEAR THE CENTER OF SANDY. HOWEVER...EARLIER DROPSONDE DATA INDICATED THAT WINDS TO HURRICANE STRENGTH WERE OCCURRING WELL TO THE SOUTH AND SOUTHWEST OF THE CENTER...BEYOND THE RADIAL LEGS COVERED BY THIS AIRCRAFT. ALTHOUGH IT COULD BE GENEROUS...THE INTENSITY IS HELD AT 65 KT FOR THIS ADVISORY. AIRCRAFT AND DROPSONDE DATA LATER TODAY SHOULD PROVIDE ADDITIONAL INFORMATION ON THE INTENSITY OF SANDY. THE VERTICAL SHEAR HAS DECREASED AND THE SYSTEM HAS BEEN MAINTAINING A SMALL AREA OF DEEP CONVECTION NEAR THE CENTER. THEREFORE...THERE IS STILL SOME SHORT-TERM POTENTIAL FOR SANDY TO INTENSIFY AS A TROPICAL CYCLONE...ESPECIALLY SINCE IT WILL BE TRAVERSING THE GULF STREAM TODAY. IN THE 24 TO 48 HOUR TIME FRAME...THE GLOBAL MODELS SHOW INTENSIFICATION OF THE CYCLONE WHICH IS UNDOUBTEDLY DUE TO BAROCLINIC PROCESSES...AS THE SYSTEM WILL BE MOVING OVER MUCH COLDER WATERS BY THAT TIME. THE OFFICIAL FORECAST SHOWS THE TRANSFORMATION TO AN EXTRATROPICAL CYCLONE BY 48 HOURS...BUT IT IS IMPORTANT TO NOTE THAT THIS HAS LITTLE OR NO BEARING ON THE OVERALL IMPACTS OF THIS DANGEROUS WEATHER SYSTEM. AFTER LANDFALL...THE DYNAMICAL GUIDANCE...AND THE OFFICIAL FORECAST...SHOW RAPID WEAKENING. THE LAST FIX FROM THE AIRCRAFT INDICATE THAT THE MOTION HAS REMAINED NEARLY THE SAME...OR 040/12. THERE ARE NO SIGNIFICANT CHANGES TO THE TRACK FORECAST REASONING FOR THIS ADVISORY. AS SANDY INTERACTS WITH A STRONG SHORTWAVE TROUGH/VORTICITY MAXIMUM APPROACHING THE U.S. EAST COAST WITHIN THE NEXT DAY OR SO...IT SHOULD TURN NORTHWARD. AFTERWARDS...SANDY SHOULD TURN NORTHWESTWARD AND WEST-NORTHWESTWARD IN THE FLOW BETWEEN THE VORTICITY MAXIMUM AND A HIGHLY ANOMALOUS MID-TROPOSPHERIC HIGH PRESSURE AREA IN THE VICINITY OF NEWFOUNDLAND. THE 0000 UTC RUNS OF THE ECMWF AND GFS MODELS ARE IN REASONABLY GOOD AGREEMENT ON THE FORECAST TRACK AND THE OFFICIAL FORECAST IS CLOSE TO THIS GUIDANCE AND THE LATEST FLORIDA STATE UNIVERSITY SUPERENSEMBLE. AS NOTED IN PREVIOUS ADVISORIES...TO AVOID A HIGHLY DISRUPTIVE CHANGE FROM TROPICAL TO NON-TROPICAL WARNINGS WHEN SANDY BECOMES POST-TROPICAL...THE WIND HAZARD NORTH OF THE TROPICAL STORM WARNING AREA WILL CONTINUE TO BE CONVEYED THROUGH HIGH WIND WATCHES AND WARNINGS ISSUED BY LOCAL NATIONAL WEATHER SERVICE OFFICES. FORECAST POSITIONS AND MAX WINDS INIT 28/0900Z 31.9N 73.3W 65 KT 75 MPH 12H 28/1800Z 33.2N 71.9W 65 KT 75 MPH 24H 29/0600Z 35.2N 70.6W 70 KT 80 MPH 36H 29/1800Z 37.7N 71.2W 70 KT 80 MPH 48H 30/0600Z 39.5N 73.7W 70 KT 80 MPH...POST-TROP/EXTRATROP 72H 31/0600Z 40.5N 77.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 96H 01/0600Z 44.0N 76.5W 30 KT 35 MPH...POST-TROP/EXTRATROP 120H 02/0600Z 47.5N 75.0W 25 KT 30 MPH...POST-TROP/EXTRATROP $$ FORECASTER PASCH/CANGIALOSI