040 
 WTNT43 KNHC 291443
 TCDAT3
  
 HURRICANE SANDY DISCUSSION NUMBER  29
 NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182012
 1100 AM EDT MON OCT 29 2012
  
 SANDY IS MAINTAINING A SMALL AREA OF DEEP CONVECTION NEAR THE
 CENTER...WITH BOTH AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT DATA
 AND VARIOUS MICROWAVE SATELLITE DATA INDICATING A 20 N MI DIAMETER
 EYE HAS DEVELOPED SINCE THE PREVIOUS ADVISORY. MAXIMUM 700 MB
 FLIGHT-LEVEL WINDS HAVE BEEN 94 KT IN THE SOUTHERN QUADRANT...AND
 SFMR-ADJUSTED SURFACE WINDS OF 80-83 KT HAVE BEEN OBSERVED IN THE
 SOUTHWESTERN QUADRANT MORE THAN 90 N MI FROM THE CENTER.  THE
 AIRCRAFT DATA ALSO INDICATE THAT THE CENTRAL PRESSURE HAS FALLEN A
 LITTLE...TO ABOUT 943 MB.  BASED ON THE LATEST RECONNAISSANCE
 DATA...THE INITIAL INTENSITY HAS BEEN INCREASED TO 80 KT.
  
 RECONNAISSANCE CENTER FIXES INDICATE THAT SANDY HAS BEEN GRADUALLY
 TURNING TO THE LEFT AND IS NOW MOVING NORTH-NORTHWESTWARD OR ABOUT
 330/16 KT. THE LATEST RECON FIXES HAVE BEEN FALLING ON THE PREVIOUS
 FORECAST TRACK...AND SO HAVE THE LATEST 12Z NHC FORECAST MODELS.
 THEREFORE...NO SIGNIFICANT CHANGES TO THE ADVISORY PREVIOUS TRACK
 OR REASONING ARE REQUIRED. SANDY IS NOW LOCATED NORTH OF THE AXIS
 OF A STRONG NEGATIVELY TILTED MID-/UPPER-LEVEL TROUGH...AND THE
 HURRICANE SHOULD TURN NORTHWESTWARD VERY SOON. LANDFALL ALONG OR
 JUST SOUTH OF THE SOUTHERN NEW JERSEY COAST IS EXPECTED LATE THIS
 EVENING...AT WHICH TIME A TURN TO THE WEST-NORTHWEST IS EXPECTED.
 AFTER MOVING INLAND OVER THE MID-ATLANTIC STATES A DECREASE IN
 FORWARD SPEED IS EXPECTED. BY 48 HOURS...THE POST-TROPICAL CYCLONE
 IS FORECAST TO MOVE NORTHWARD AND THEN NORTHEASTWARD. THE OFFICIAL
 NHC FORECAST TRACK IS SIMILAR TO THE PREVIOUS ADVISORY TRACK...AND
 LIES CLOSE TO A BLEND OF THE CONSENSUS MODELS TV15 AND TVCN.
  
 SANDY IS CURRENTLY TRAVERSING A NARROW RIDGE OF WARM SSTS AROUND
 27C...WHICH ARE ASSOCIATED WITH THE GULF STREAM. THIS EXTRA
 LOW-LEVEL HEAT INPUT HAS LIKELY CONTRIBUTED TO THE RECENT INCREASE
 IN CONVECTION AROUND THE EYE. HOWEVER...SANDY WILL BE MOVING OVER
 THE NORTH WALL OF THE GULFSTREAM WITHIN THE NEXT 3 HOURS...WHICH
 WILL BRING A HALT TO ANY SIGNIFICANT INNER-CORE CONVECTIVE
 DEVELOPMENT. HOWEVER...THIS SHOULD HAVE LITTLE IMPACT ON THE
 OVERALL INTENSITY OR THE SIZE OF THE EXTREMELY LARGE WIND FIELD
 THAT IS NOW MORE THAN 1000 N MI IN DIAMETER. AT THE MOMENT...
 HURRICANE FORCE WINDS ARE ONLY OCCURRING IN THE SOUTHWEST
 QUADRANT...BUT MODEL GUIDANCE SUGGESTS THAT THESE COULD SPREAD INTO
 THE NORTHERN SEMICIRCLE BEFORE LANDFALL.
  
 SURFACE DATA INDICATE THAT WELL-DEFINED WARM AND COLD FRONTS LIE
 VERY NEAR THE CENTER OF SANDY...AND THE COMBINATION OF COLDER OCEAN
 WATER AND NEARBY FRONTAL SYSTEMS ARE EXPECTED TO RESULT IN
 EXTRATROPICAL TRANSITION BEFORE THE CENTER OF THE CYCLONE REACHES
 THE COAST.  HOWEVER...THIS TRANSFORMATION WILL NOT DIMINISH THE
 OVERALL IMPACTS FROM WINDS TO HURRICANE STRENGTH...LIFE-THREATENING
 STORM SURGE... AND FLOODING RAINS ASSOCIATED WITH THIS DANGEROUS
 WEATHER SYSTEM.  BASED ON THE GLOBAL MODELS...THE CYCLONE SHOULD
 WEAKEN FAIRLY RAPIDLY AFTER LANDFALL.
  
 INTERESTS ARE REMINDED NOT TO FOCUS ON THE CENTER OR THE EXACT
 FORECAST TRACK OF THIS SYSTEM...SINCE STRONG WINDS COVER AN AREA
 SEVERAL HUNDRED MILES ACROSS...AND THE HIGHEST WINDS WILL NOT
 NECESSARILY BE NEAR THE CENTER...ESPECIALLY JUST A FEW HUNDRED FEET
 ABOVE THE GROUND.
  
 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  29/1500Z 37.5N  71.5W   80 KT  90 MPH
  12H  30/0000Z 39.0N  74.0W   80 KT  90 MPH...POST-TROP/EXTRATROP
  24H  30/1200Z 39.9N  76.7W   60 KT  70 MPH...POST-TROP/EXTRATROP
  36H  31/0000Z 40.4N  77.9W   45 KT  50 MPH...POST-TROP/EXTRATROP
  48H  31/1200Z 41.5N  77.2W   35 KT  40 MPH...POST-TROP/EXTRATROP
  72H  01/1200Z 44.5N  75.6W   30 KT  35 MPH...POST-TROP/EXTRATROP
  96H  02/1200Z 45.9N  72.7W   25 KT  30 MPH...POST-TROP/EXTRATROP
 120H  03/1200Z 47.5N  68.5W   20 KT  25 MPH...POST-TROP/EXTRATROP
  
 $$
 FORECASTER STEWART