000
WTNT43 KNHC 231445
TCDAT3
 
TROPICAL STORM SANDY DISCUSSION NUMBER   5
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182012
1100 AM EDT TUE OCT 23 2012
 
THE CLOUD PATTERN OF THE STORM IS GRADUALLY BECOMING BETTER
ORGANIZED...WITH A LARGE CURVED BAND FEATURE EVIDENT OVER THE
EASTERN AND SOUTHERN PORTIONS OF THE CIRCULATION.  USING A BLEND OF
SFMR AND FLIGHT-LEVEL WIND DATA FROM THE HURRICANE HUNTERS...THE
CURRENT INTENSITY IS SET TO 45 KT.  THE UPPER-LEVEL OUTFLOW IS WELL
DEFINED OVER THE EASTERN PART OF THE CYCLONE BUT IS RESTRICTED TO
THE NORTHWEST.  GIVEN THE ENVIRONMENT OF LOW SHEAR AND HIGH OCEANIC
HEAT CONTENT...SANDY IS LIKELY TO STRENGTHEN INTO A HURRICANE IN 12
TO 24 HOURS...AND THE OFFICIAL FORECAST IS CLOSE TO THE
STATISTICAL-DYNAMICAL LGEM GUIDANCE.  THE INTERACTION OF THE
CIRCULATION OF SANDY WITH THE MOUNTAINOUS TERRAIN OF EASTERN CUBA
SHOULD CAUSE SOME WEAKENING.  AFTERWARDS...THE DYNAMICAL GUIDANCE
SHOWS THE VERTICAL SHEAR INCREASING TO NEAR 30 KT WHICH SHOULD
LIMIT RE-INTENSIFICATION.  AROUND DAY 5...THE GFS OUTPUT SUGGESTS
THAT SANDY WILL BE DERIVING ENERGY FROM BAROCLINIC SOURCES...AND
THE NHC FORECAST SHOWS THE SYSTEM AS POST-TROPICAL BY THAT TIME. 

FIXES FROM THE AIRCRAFT SHOW A NORTH-NORTHEASTWARD MOTION...OR ABOUT
020/4.  AS THE MID-LEVEL RIDGE TO THE NORTH OF SANDY GRADUALLY
WEAKENS...THE TROPICAL CYCLONE SHOULD MOVE NORTH-NORTHEASTWARD TO
NORTHWARD WITH SOME INCREASE IN FORWARD SPEED.  IN AROUND 2-3
DAYS...THE TRACK COULD BEND A LITTLE TO THE LEFT DUE TO THE
INFLUENCE OF AN UPPER-LEVEL TROUGH JUST TO THE WEST OF SANDY.  THIS
IS SHOWN MOST PROMINENTLY IN THE 0600 UTC GFS RUN...WHICH HAS
SHIFTED WESTWARD FROM ITS PREVIOUS SOLUTION.  THE OFFICIAL TRACK
FORECAST IS NUDGED WESTWARD FROM THE PREVIOUS ONE IN THE 48 TO 72
HOUR TIME FRAME.  THIS IS VERY CLOSE TO THE LATEST DYNAMICAL TRACK
MODEL CONSENSUS...AND ALSO SIMILAR TO THE FSU SUPERENSEMBLE
PREDICTION.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/1500Z 13.8N  77.8W   45 KT  50 MPH
 12H  24/0000Z 14.9N  77.6W   55 KT  65 MPH
 24H  24/1200Z 16.9N  77.2W   65 KT  75 MPH
 36H  25/0000Z 18.9N  77.0W   70 KT  80 MPH
 48H  25/1200Z 21.4N  76.8W   60 KT  70 MPH...ON NORTH COAST OF CUBA
 72H  26/1200Z 25.6N  76.5W   60 KT  70 MPH
 96H  27/1200Z 28.5N  74.5W   60 KT  70 MPH
120H  28/1200Z 31.0N  70.5W   60 KT  70 MPH...POST-TROPICAL
 
$$
FORECASTER PASCH