000
WTNT44 KNHC 190849
TCDAT4
 
SUBTROPICAL STORM MELISSA DISCUSSION NUMBER   4
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL142013
500 AM AST TUE NOV 19 2013
 
MELISSA APPEARS TO HAVE STRENGTHENED A LITTLE OVERNIGHT. ALTHOUGH
THE CYCLONE IS NOT PRODUCING WIDESPREAD DEEP CONVECTION...A FEW
BANDS HAVE BECOME BETTER ESTABLISHED TO THE NORTH OF THE CENTER
DURING THE LAST FEW HOURS. THE INITIAL WIND SPEED IS NUDGED UPWARD
TO 55 KT...IN AGREEMENT WITH THE LATEST SATELLITE INTENSITY
ESTIMATE FROM TAFB. THE CIRCULATION OF THE CYCLONE IS GRADUALLY
BECOMING MORE CIRCULAR AND THE CLOUD PATTERN APPEARS TO BE
CONTRACTING WHILE IT SEPARATES FROM THE NEARBY FRONTAL BOUNDARY. A
DECREASE IN SHEAR DURING THE NEXT 12 TO 24 HOURS COULD ALLOW
MELISSA TO STRENGTHEN A LITTLE AND TRANSITION TO A TROPICAL
CYCLONE. ANY STRENGTHENING SHOULD COME TO AN END IN 24 TO 36 HOURS
WHEN THE STORM IS EXPECTED TO MOVE OVER SIGNIFICANTLY COLDER WATER
AND INTO A DRIER AIRMASS. MELISSA IS ANTICIPATED TO BECOME
POST-TROPICAL IN ABOUT 48 HOURS WHEN IT IS FORECAST TO BE OVER SEA
SURFACE TEMPERATURES OF ABOUT 18 C.
 
THE SUBTROPICAL STORM HAS TURNED TO THE NORTH...WITH THE LATEST
INITIAL MOTION ESTIMATE BEING 360/8 KT. A DEEP-LAYER TROUGH AND
ASSOCIATED COLD FRONT LOCATED OVER THE WESTERN ATLANTIC WILL BE
MOVING CLOSER TO MELISSA...AND WILL HELP ACCELERATE THE CYCLONE
NORTHEASTWARD DURING THE NEXT COUPLE OF DAYS. BEYOND A COUPLE OF
DAYS...THERE IS A NOTABLE DISAGREEMENT IN HOW THE POST-TROPICAL
REMNANT OF MELISSA INTERACTS WITH THE DEEP-LAYER TROUGH. THE GFS
CONTINUES TO SHOW THE CYCLONE ROTATING AROUND THE EASTERN SIDE OF
THE TROUGH OR LOW...WHILE THE ECMWF AND UKMET SHOW THE CYCLONE
MOVING MORE EASTWARD IN THE WESTERLIES. THE NHC FORECAST IS
ADJUSTED A LITTLE TO THE EAST OF THE PREVIOUS ONE...AND LIES CLOSE
TO THE FLORIDA STATE SUPERENSEMBLE...WHICH IS IN BETWEEN THE
AFOREMENTIONED SCENARIOS.
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  19/0900Z 31.2N  54.6W   55 KT  65 MPH
 12H  19/1800Z 32.6N  53.5W   60 KT  70 MPH
 24H  20/0600Z 35.3N  50.3W   60 KT  70 MPH
 36H  20/1800Z 38.4N  45.5W   55 KT  65 MPH
 48H  21/0600Z 41.3N  39.5W   55 KT  65 MPH...POST-TROPICAL
 72H  22/0600Z 46.5N  30.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  23/0600Z 52.0N  27.0W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  24/0600Z...DISSIPATED
 
$$
FORECASTER CANGIALOSI