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Hurricane SANDY


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HURRICANE SANDY DISCUSSION NUMBER  27
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182012
1100 PM EDT SUN OCT 28 2012

THE CONVECTION NEAR THE CENTER OF SANDY HAS BECOME A LITTLE BETTER
ORGANIZED THIS EVENING...WITH A NOAA HURRICANE HUNTER AIRCRAFT
REPORTING A 25-35 MILE WIDE EYE WITH AN OPEN EYEWALL.  HOWEVER...
THE STRONGEST WINDS IN THE STORM ARE NOT OCCURRING IN THE
EYEWALL...AS THE NOAA AND AIR FORCE RESERVE AIRCRAFT FOUND A LARGE
AREA OF AT LEAST 60 KT SURFACE WINDS ABOUT 100-120 N MI SOUTHWEST
OF THE CENTER.  IN ADDITION...THE AIR FORCE PLANE REPORTED 700-MB
FLIGHT-LEVEL WINDS OF 102 KT.  BASED ON THESE DATA...AND THE
LIKELIHOOD THAT THE STRONGEST WINDS WERE NOT SAMPLED...THE INITIAL
INTENSITY REMAINS 65 KT.

SANDY HAS TURNED A LITTLE TO THE LEFT DURING THE PAST FEW HOURS...
WITH THE INITIAL MOTION NOW 035/12.  THERE IS LITTLE CHANGE TO THE
TRACK GUIDANCE OR THE FORECAST TRACK SINCE THE PREVIOUS ADVISORY...
WITH SANDY EXPECTED TO TURN NORTHWARD DURING THE NEXT SEVERAL HOURS
AND NORTHWESTWARD ON MONDAY.  THE FORECAST TRACK BRINGS THE CENTER
NEAR OVER THE COAST OF THE MID-ATLANTIC STATES IN ABOUT 30 HOURS...
AND IT SHOULD BE NOTED THAT SOME OF THE GUIDANCE HAS AN EARLIER
LANDFALL TIME THAN THE OFFICIAL FORECAST.  AFTER LANDFALL...SANDY
IS EXPECTED TO MERGE WITH THE DEEP-LAYER BAROCLINIC TROUGH OVER THE
EASTERN UNITED STATES AND GRADUALLY TURN NORTHWARD.  A TURN TOWARD
THE EAST IS LIKELY BY THE END OF THE FORECAST PERIOD IF SANDY
SURVIVES THAT LONG.

VERTICAL WIND SHEAR HAS DECREASED OVER SANDY...AND THE CENTER IS
MOVING OVER A LOCALLY WARMER PATCH OF WATER.  THESE CONDITIONS MAY
HAVE ALLOWED THE EYEWALL FORMATION...AND THEY COULD LEAD TO SOME
STRENGTHENING IN ADDITION TO THAT CAUSED BY BAROCLINIC PROCESSES. 
HOWEVER...SURFACE AND UPPER-AIR DATA SHOW THAT THE PROCESS OF
EXTRATROPICAL TRANSITION IS BEGINNING...WITH THE LOW-LEVEL COLD
FRONT NOW INTERACTING WITH THE WEST SIDE OF THE CIRCULATION.  THIS
TRANSITION IS EXPECTED TO BE COMPLETE WITHIN 24 HOURS...BUT IT WILL
NOT DIMINISH THE OVERALL IMPACTS FROM WINDS TO HURRICANE
STRENGTH...LIFE-THREATENING STORM SURGE...AND FLOODING RAINS
ASSOCIATED WITH THIS DANGEROUS WEATHER SYSTEM.  SANDY IS EXPECTED
TO WEAKEN AFTER LANDFALL.
 
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  29/0300Z 34.5N  70.5W   65 KT  75 MPH
 12H  29/1200Z 36.4N  70.9W   65 KT  75 MPH
 24H  30/0000Z 38.7N  73.2W   70 KT  80 MPH...POST-TROP/EXTRATROP
 36H  30/1200Z 39.8N  75.8W   60 KT  70 MPH...POST-TROP/EXTRATROP
 48H  31/0000Z 40.6N  77.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  01/0000Z 43.5N  77.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  02/0000Z 45.5N  75.0W   25 KT  30 MPH...POST-TROP/EXTRATROP
120H  03/0000Z 46.0N  70.0W   25 KT  30 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER BEVEN
 
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