000 AGXX40 KNHC 081919 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 220 PM EST SAT DEC 8 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLC...AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... FAIRLY BENIGN PATTERN IN PLACE ACROSS THE GULF WITH A FEW MINOR SURFACE FEATURES INCLUDING A WEAK TROUGH OVER THE N-CENTRAL GULL OF MEXICO. NEXT SIGNIFICANT FEATURE COMING INTO PLAY IS A COLD FRONT SLATED TO MOVE OFF THE TEXAS COAST EARLY ON MON. UTILIZED A BLEND OF THE ECMWF/GFS REGARDING THE TIMING OF THE FRONT AS MOTH MODEL SOLUTIONS WERE QUITE SIMILAR. NORTHERLY WINDS BEHIND THE FRONT ARE NOT EXPECTED TO REACH GALE FORCE WITH THE GFS DEPICTING THE HIGHEST WINDS. THE 30-M WINDS FROM THE MODEL BRIEFLY TOUCH 35-KT AROUND 00Z TUE THEN SUBSIDE. THE PROGRESSIVE NATURE OF THE SHORTWAVE TROUGH SUPPORTS ONLY LIMITED CAA. MWW3/ECMWF WW BOTH INDICATE SEAS UP TO 9-10 FT LATE MON AND TUE IN SW GULF. IN ANY EVENT THE FRONT IS EXPECTED TO SWEEP RAPIDLY SE AND EXTEND FROM SE LOUISIANA TO VERACRUZ BY MON EVENING...AND FROM THE FLORIDA BIG BEND THROUGH 25N90W TO THE WESTERN BAY OF CAMPECHE BY LATE TUE. THE FRONT STALLS AND WEAKENS FROM SW FLORIDA TO 24N90W TO SW BAY OF CAMPECHE WED THEN DISSIPATES THU AS RIDGE OF HIGH PRES BUILDS ACROSS THE GULF STATES AND LOW LEVEL FLOW PARALLELS THE FRONT. SW N ATLC S OF 31N W OF 65W... 12Z SFC ANALYSIS DEPICTED A WEAKENING COLD FRONT ENTERING THE AREA NEAR 31N78W TO NE FLORIDA WITH STRENGTHENING HIGH PRES BUILDING NE OF THE AREA. RIDGE BUILDS WESTWARD ALONG 26N/27N SUN AND MON WITH INCREASING E-SE TRADE WINDS S OF 28N. SW WINDS WILL INCREASE W OF 75W MON INTO TUE AS A SLOW MOVING COLD FRONT APPROACHES THE SE COAST. THE FRONT ENTERS THE FAR NW PORTION OF THE AREA OVERNIGHT TUE/WED IN MORE AGREEMENT WITH ECMWF MODEL VICE THE GFS AS THE ECMWF MODEL IS PREFERRED IN THE HPC MEDIUM RANGE DISCUSSION. INITIAL SHORTWAVE TROUGH WHICH SWEEPS THROUGH THE GULF STATES LATE MON AND TUE IS REINFORCED BY ANOTHER SHORTWAVE WHICH AMPLIFIES AS IT MOVES TOWARD THE E COAST OF THE CONUS. THIS RESULTS IN CYCLOGENESIS ALONG THE FRONT N OF THE AREA WITH INCREASING NW TO N WINDS BEHIND THE COLD FRONT BY LATE WED. COLD FRONT EXTENDS FROM 31N76W TO NE FLORIDA LATE WED AND FROM 31N66W TO THE NORTHERN BAHAMAS BY LATE THU. CARIBBEAN SEA AND TROPICAL N ATLC S OF 19N W OF 55W... 1354 UTC ASCAT PASS INDICATED A LARGER AREA OF MODERATE TRADES ACROSS THE CARIBBEAN THAN PREVIOUSLY INDICATED WITH 20 TO LOCALLY 25 KT WINDS NOTED WITHIN THE ASCAT SWATH GENERALLY FROM 11N TO 17N. THE INITIAL WIND FIELD HAS BEEN ADJUSTED ACCORDINGLY. THE AREA OF 20-25 KT TRADES REACH THEIR MAXIMUM AREAL EXTENT LATE SUN AND MON WITH WINDS REACHING 30 KT WITHIN 90 NM OF THE COAST OF COLOMBIA BY SUN NIGHT INTO EARLY TUE. MEANWHILE AS STRONG HIGH PRES BUILDS OVER THE WEST-CENTRAL ATLC LATE MON THROUGH WED WINDS AND SEAS INCREASE TO 20-25 KT OVER A LARGE PORTION OF THE TROPICAL ATLC N OF 13N THEN SPREAD WESTWARD AND MERGE WITH THE TRADES IN THE CARIBBEAN. MWW3/ECMWF WAVE MODELS IN AGREEMENT IN DEPICTING PEAK 10-11 FT SEAS BY WED. AS THE COLD FRONT OVER THE SW N ATLC SLIPS SE AND E-CENTRAL HIGH PRES YIELDS...TRADES SUBSIDE TO 20 KT AND SEAS TO 9 FT OVER THE AREA. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .NONE. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER COBB