000
WTNT43 KNHC 280246
TCDAT3
 
HURRICANE SANDY DISCUSSION NUMBER  23
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182012
1100 PM EDT SAT OCT 27 2012
 
SATELLITE IMAGERY SHOWS THAT THE CENTRAL CONVECTION ASSOCIATED WITH
SANDY HAS INCREASED DURING THE EVENING.  IN ADDITION...DATA FROM AIR
FORCE RESERVE AND NOAA HURRICANE HUNTER AIRCRAFT INDICATE THAT THE
CIRCULATION AT 10000-12000 FT IS STRONGER THAN 24 HOURS AGO...AND
THERE ARE INDICATIONS OF AN INNER WIND MAXIMUM NEAR THE CONVECTION. 
HOWEVER...THIS HAS NOT YET RESULTED IN ANY INTENSIFICATION...AND THE
INITIAL INTENSITY REMAINS NEAR 65 KT.  THE AIRCRAFT-REPORTED
PRESSURE IS ABOUT 960 MB. 

SANDY HAS MOVED A LITTLE TO THE RIGHT DURING THE PAST SEVERAL
HOURS...WITH AN INITIAL MOTION OF 040/12.  OTHER THAN THAT...THERE
IS NO CHANGE TO THE TRACK FORECAST PHILOSOPHY.  SANDY IS EXPECTED
TO MOVE GENERALLY NORTHEASTWARD FOR THE NEXT 24 HOURS OR SO...
STEERED BY A DEEP-LAYER TROUGH MOVING INTO THE EASTERN UNITED
STATES.  AFTER THAT...A DEVELOPING MID/UPPER-LEVEL RIDGE OVER
NORTHEASTERN CANADA AND INTERACTION WITH THE U. S. TROUGH SHOULD
CAUSE THE CYCLONE TO TURN TOWARD THE NORTH...NORTHWEST...AND
EVENTUALLY WEST-NORTHWEST.  THIS MOTION SHOULD BRING THE CENTER
INLAND OVER THE MID-ATLANTIC REGION BETWEEN 48-72 HOURS.  AFTER
LANDFALL...SANDY IS EXPECTED TO MERGE WITH THE U. S. TROUGH TO FORM
A LARGE DEEP-LAYER LOW PRESSURE AREA...WITH THE RESULTING SYSTEM
MOVING NORTHWARD AND NORTHEASTWARD AFTER 72 HOURS.  AS NOTED IN THE
PREVIOUS ADVISORY...IT IS STILL TOO SOON TO FOCUS ON THE EXACT
TRACK...BOTH BECAUSE OF FORECAST UNCERTAINTY AND BECAUSE THE
IMPACTS ARE GOING TO COVER SUCH A LARGE AREA AWAY FROM THE CENTER.

SANDY REMAINS IN AN AREA OF STRONG UPPER-LEVEL DIVERGENCE CAUSED BY
A TROUGH TO ITS SOUTHWEST.  THIS IS LIKELY HELPING TO SUSTAIN THE
HURRICANE DESPITE SIGNIFICANT VERTICAL WIND SHEAR.  WHILE THE
INTENSITY FORECAST SHOWS LITTLE CHANGE IN STRENGTH FOR 36 HOURS...
THE SHIPS MODEL AND THE DYNAMICAL MODELS SUGGEST THE POSSIBILITY
THE SHEAR COULD DECREASE DURING THIS TIME...AND IF THAT HAPPENS
SANDY COULD STRENGTHEN A LITTLE AS A TROPICAL CYCLONE.  AFTER 36
HOURS...THE DYNAMICAL MODELS ALL FORECAST THAT INTERACTION WITH THE
U. S. TROUGH SHOULD CAUSE SOME INTENSIFICATION ALONG WITH
EXTRATROPICAL TRANSITION...WHICH IS FORECAST TO BE COMPLETE BY 48
HOURS.  IT SHOULD BE NOTED THAT THIS TRANSITION WILL HAVE LITTLE
EFFECT ON THE SIZE AND IMPACTS OF THIS LARGE AND VIGOROUS SYSTEM. 
AFTER LANDFALL...THE FORECAST AGAIN CALLS FOR THE CYCLONE TO
STEADILY WEAKEN.
 
AS ALSO NOTED IN THE PREVIOUS ADVISORY...IN ORDER TO AVOID THE RISK
OF 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  28/0300Z 30.9N  74.3W   65 KT  75 MPH
 12H  28/1200Z 32.2N  72.9W   65 KT  75 MPH
 24H  29/0000Z 34.1N  71.4W   65 KT  75 MPH
 36H  29/1200Z 36.3N  71.1W   65 KT  75 MPH
 48H  30/0000Z 38.7N  72.4W   70 KT  80 MPH...POST-TROP/EXTRATROP
 72H  31/0000Z 40.5N  77.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  01/0000Z 43.5N  77.0W   30 KT  35 MPH...POST-TROP/EXTRATROP
120H  02/0000Z 47.5N  75.0W   25 KT  30 MPH...POST-TROP/EXTRATROP
 
$$
FORECASTER BEVEN