000
WTNT44 KNHC 210837
TCDAT4

TROPICAL STORM MELISSA DISCUSSION NUMBER  12
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142013
500 AM AST THU NOV 21 2013

EVEN THOUGH MELISSA IS CURRENTLY OVER QUITE COOL 21 C SEA SURFACE
TEMPERATURES...THE STORM IS STILL PRODUCING DEEP CONVECTION AND IS
HOLDING ON TO TROPICAL CYCLONE STATUS. THE MAIN REASONS THE STORM IS
ABLE TO REMAIN TROPICAL OVER THE COOL WATER IS BECAUSE OF THE
COMBINED FACTORS OF A COLD AIRMASS ALOFT AND FAIRLY LOW WIND SHEAR.
THE CLOUD PATTERN STILL CONSISTS OF FRAGMENTED CURVED BANDS MAINLY
CONFINED TO THE WESTERN PORTION OF THE CIRCULATION...AND THE DVORAK
CLASSIFICATIONS STILL SUPPORT AN INTENSITY OF 45 KT. MOST OF THE
MODELS SHOW MELISSA CHANGING LITTLE IN STRENGTH OVER THE NEXT
COUPLE OF DAYS...BUT THE SYSTEM WILL LIKELY BE LOSING ITS TROPICAL
CHARACTERISTICS DURING THE NEXT 12 TO 24 HOURS WHILE IT MOVES OVER
SEA SURFACE TEMPERATURES LOWER THAN 20 C. AFTER THE CYCLONE BECOMES
POST-TROPICAL...A GRADUAL WEAKENING IS PREDICTED WITH DISSIPATION
EXPECTED IN 3 TO 4 DAYS.

MELISSA CONTINUES TO RACE EAST-NORTHEASTWARD AT 28 KT EMBEDDED IN
THE STRONG MID-LATITUDE FLOW TO THE SOUTHEAST OF A LARGE
EXTRATROPICAL CYCLONE. A DECREASE IN FORWARD SPEED AND A TURN TO
THE EAST AND THEN SOUTHEAST ARE EXPECTED OVER THE NEXT FEW DAYS. THE
NHC FORECAST IS AGAIN ADJUSTED SOUTHWARD...FOLLOWING THE LATEST
TREND IN THE GUIDANCE.

GALE-FORCE WINDS ARE EXPECTED TO SPREAD ACROSS THE WESTERN AND
CENTRAL AZORES LATE TODAY OR TONIGHT AFTER MELISSA LOSES TROPICAL
CHARACTERISTICS.

FORECAST POSITIONS AND MAX WINDS

INIT  21/0900Z 39.1N  38.5W   45 KT  50 MPH
 12H  21/1800Z 40.2N  33.6W   45 KT  50 MPH
 24H  22/0600Z 41.5N  27.7W   45 KT  50 MPH...POST-TROPICAL
 36H  22/1800Z 42.2N  22.8W   45 KT  50 MPH...POST-TROP/EXTRATROP
 48H  23/0600Z 42.2N  19.8W   40 KT  45 MPH...POST-TROP/EXTRATROP
 72H  24/0600Z 40.0N  16.5W   30 KT  35 MPH...POST-TROP/EXTRATROP
 96H  25/0600Z...DISSIPATED

$$
FORECASTER CANGIALOSI