Tropical Storm SANDY

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TROPICAL STORM SANDY DISCUSSION NUMBER   8
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182012
500 AM EDT WED OCT 24 2012
 
REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT ABOUT 
4 HOURS AGO INDICATED 850-MB FLIGHT-LEVEL WINDS OF 68 KT AND
SFMR-ADJUSTED SURFACE WIND ESTIMATES OF 55 KT. THE MINIMUM CENTRAL
PRESSURE WAS ESTIMATED TO BE 986 MB. SINCE THEN...DEEP CONVECTION
WITH CLOUD TOPS AS COLD AS -90C HAVE ALMOST COMPLETELY ENCIRCLED
THE CENTER OF SANDY AND NOAA BUOY 42058 RECENTLY REPORTED A
SUSTAINED WIND OF 49 KT WITH A GUST TO 64 KT MORE THAN 160 N MI
EAST OF THE CENTER. BASED ON THESE DATA...THE INITIAL INTENSITY IS
RAISED TO 60 KT.
 
SANDY IS MOVING FASTER TOWARD THE NORTH NOW...OR 010/12 KT. THE
FORECAST SCENARIO AND THE FORECAST TRACK REMAIN UNCHANGED THROUGH
48-72 HOURS. SANDY SHOULD MOVE GENERALLY NORTHWARD FOR THE NEXT 48
HOURS AS THE CYCLONE INTERACTS OR MERGES WITH A POTENT MID- TO
UPPER-LEVEL TROUGH SITUATED TO ITS NORTHWEST AND A MID-LEVEL RIDGE
TO THE NORTH THAT IS SLIDING EASTWARD. AFTER 72 HR...SOUTHWESTERLY
MID/UPPER-LEVEL FLOW ASSOCIATED WITH A SECOND DIGGING TROUGH OVER
THE EASTERN UNITED STATES IS FORECAST TO TURN THE CYCLONE
NORTHEASTWARD. THE NHC MODEL GUIDANCE HAS TRENDED A LITTLE MORE
NORTH AND WEST AFTER 72 HOURS...AND THE OFFICIAL FORECAST TRACK HAS
BEEN NUDGED IN THAT DIRECTION. THE NEW FORECAST TRACK LIES NEAR THE
CENTER OF THE GUIDANCE ENVELOPE...AND IS BETWEEN THE PREVIOUS
ADVISORY TRACK AND THE CONSENSUS MODELS TVCA AND TV15...AND THE
FLORIDA STATE SUPERENSEMBLE MODEL.
 
ENVIRONMENTAL CONDITIONS ARE EXPECTED TO REMAIN FAVORABLE FOR
ADDITIONAL STRENGTHENING TO OCCUR UP UNTIL SANDY MAKES LANDFALL ON
JAMAICA IN ABOUT 12 HOURS OR SO. AFTER THAT...LAND INTERACTION WITH
JAMAICA AND EASTERN CUBA...COMBINED WITH INCREASING SOUTHWESTERLY
VERTICAL WIND SHEAR SHOULD INDUCE SOME GRADUAL WEAKENING.
HOWEVER...THE AMOUNT OF WEAKENING THAT TYPICALLY OCCURS UNDER SUCH
NEGATIVE CONDITIONS IS EXPECTED TO BE LIMITED DUE TO STRONG
BAROCLINIC INTERACTION/FORCING ASSOCIATED WITH THE STRONG
UPPER-LEVEL TROUGH. THE NHC INTENSITY FORECAST FOLLOWS THE TREND OF
THE PREVIOUS ADVISORY IN SHOWING A 60-KT INTENSITY AFTER 36 HOURS
AND THE CYCLONE BECOMING POST-TROPICAL BY 120 HOURS.  HOWEVER...
THIS REMAINS A LOW CONFIDENCE FORECAST FOR BOTH THE INTENSITY AND
THE STRUCTURE OF THE CYCLONE AFTER 48-72 HOURS DUE TO UNCERTAINTY
IN THE AMOUNT OF BAROCLINIC INTERACTION.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  24/0900Z 16.3N  77.0W   60 KT  70 MPH
 12H  24/1800Z 17.9N  76.8W   70 KT  80 MPH...NEAR JAMAICA
 24H  25/0600Z 20.6N  76.5W   65 KT  75 MPH...INLAND EASTERN CUBA
 36H  25/1800Z 23.3N  76.5W   60 KT  70 MPH...OVER WATER
 48H  26/0600Z 25.7N  76.6W   60 KT  70 MPH
 72H  27/0600Z 28.2N  76.3W   60 KT  70 MPH
 96H  28/0600Z 31.0N  73.6W   60 KT  70 MPH
120H  29/0600Z 33.4N  70.3W   60 KT  70 MPH...POST-TROPICAL
 
$$
FORECASTER STEWART
 
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