Subtropical Storm MELISSA

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SUBTROPICAL STORM MELISSA DISCUSSION NUMBER   7
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142013
1100 PM AST TUE NOV 19 2013
 
THE SATELLITE APPEARANCE OF MELISSA IS LESS IMPRESSIVE THAN A FEW
HOURS AGO...WITH JUST A SMALL AREA OF CONVECTION FORMING NEAR AND
NORTHEAST OF THE CENTER.  THE SYSTEM DOES NOT APPEAR TO BE ANY MORE
TROPICAL THAN EARLIER...SO IT IS BEING KEPT AS A SUBTROPICAL STORM.
THE INITIAL INTENSITY IS LOWERED TO 45 KT IN ACCORDANCE WITH ASCAT
DATA AND THE LATEST TAFB SATELLITE ESTIMATE.  ALTHOUGH MELISSA IS
FORECAST TO MOVE OVER COLDER WATERS SOON...A LARGE INCREASE IN
FORWARD SPEED AND SOME NON-TROPICAL FORCING COULD OFFSET THE
DECREASING WATER TEMPERATURES.  THUS LITTLE CHANGE IN STRENGTH IS
FORECAST FOR THE NEXT 48 HOURS...WHICH IS LOWER THAN THE PREVIOUS
NHC PREDICTION...AND IS NEAR THE MODEL CONSENSUS. MELISSA COULD
STILL BECOME A TROPICAL STORM IN THE NEXT DAY OR SO BEFORE MOVING
OVER COLDER WATERS.  SOME WEAKENING IS FORECAST AFTER 48 HOURS DUE
TO EXTREMELY COLD WATER AND LOSS OF BAROCLINIC FORCING.  MELISSA IS
EXPECTED TO TRANSITION INTO A POST-TROPICAL CYCLONE WITHIN 36 HOURS
DUE TO THE COLDER WATERS...AND INTO AN EXTRATROPICAL CYCLONE IN
ABOUT 3 DAYS.
 
THE STORM IS MOVING TO THE NORTHEAST AT ABOUT 15 KT.  MODEL
GUIDANCE REMAINS IN EXCELLENT AGREEMENT ON MELISSA ACCELERATING TO
THE NORTHEAST AND EAST-NORTHEAST OVER THE NEXT 48H AHEAD OF A LARGE
MID-LATITUDE TROUGH.  THE LATEST CONSENSUS HAS SHIFTED EASTWARD...
AND THE NHC FORECAST FOLLOWS SUIT.  THE CYCLONE WILL PROBABLY BE
ABSORBED BY A LARGER LOW AND/OR ASSOCIATED FRONTAL SYSTEM WITHIN
96 HOURS...IF NOT SOONER.
 
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  20/0300Z 33.6N  52.4W   45 KT  50 MPH
 12H  20/1200Z 35.7N  49.2W   45 KT  50 MPH
 24H  21/0000Z 38.4N  43.7W   45 KT  50 MPH
 36H  21/1200Z 40.8N  37.7W   45 KT  50 MPH...POST-TROPICAL
 48H  22/0000Z 43.0N  31.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
 72H  23/0000Z 48.0N  25.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  24/0000Z 54.0N  23.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  25/0000Z...DISSIPATED
 
$$
FORECASTER BLAKE
 
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