000 AGXX40 KNHC 191909 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 210 PM EST WED DEC 19 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... A WEAK COLD FRONT IS GLIDING THROUGH THE FAR SOUTHEAST GULF OF MEXICO THIS AFTERNOON...WITH 1020 MB HIGH PRES BUILDING OVER THE NE COAST OF FLORIDA. BUOY AND PLATFORM DATA OVER THE NW GULF ARE SHOWING 20 KT SOUTHERLY RETURN FLOW BETWEEN THE HIGH PRES AND A COMPLEX LOW DIGGING INTO THE SOUTHERN PLAINS. GLOBAL MODELS ARE IN GOOD AGREEMENT SHOWING THE SUPPORTING UPPER TROUGH FOR THIS LOW PUSHING INTO THE MISSISSIPPI VALLEY TOMORROW...WITH THE ASSOCIATED COLD FRONT MOVING OFF THE TEXAS COAST BY EARLY MORNING. THE COMBINATION OF A TIGHT PRES GRADIENT ALONG WITH DECENT COLD AIR ADVECTION WILL ALLOW WINDS TO MARKEDLY INCREASE BEHIND THE FRONT. NOT ONLY ARE GLOBAL MODELS IN VERY GOOD AGREEMENT...SHORT RANGE ENSEMBLE OUTPUT IS SHOWING A VERY HIGH CHANCE OF WINDS TO GALE FORCE BEHIND THE FRONT OVER THE WESTERN GULF THU...WITH GALES PERSISTING OVER THE FAR SW GULF INTO FRI. THE OFFICIAL FORECAST FOR THE OFFSHORE WATERS IS IN LINE WITH ADJOINING COASTAL FORECASTS FOR THE SOUTH TEXAS COAST INDICATING WINDS APPROACHING GALE FORCE EARLY THU...WITH UNSTABLE CONDITIONS DUE TO THE COLD AIR ADVECTION ALLOWING FREQUENT GUSTS TO GALE FORCE. SUSTAINED WINDS WILL REACH GALE FORCE BY LATE THU ACROSS MUCH OF THE WESTERN GULF W OF 96W. THE FRONT WILL SWEEP RAPIDLY ACROSS THE GULF...CLEARING THE SE GULF BY EARLY FRI AND FOLLOWED BY FRESH TO STRONG FLOW OVER THE CENTRAL AND EASTERN GULF. THE PATTERN REMAINS FAIRLY DRY...AND NO SIGNIFICANT AREAS OF CONVECTION ARE EXPECTED WITH THE FRONTAL PASSAGE. WINDS AND LATER SEAS WILL START TO DIMINISH FROM NW TO SE ACROSS THE GULF FRI THROUGH SAT. GENERALLY LIGHT TO MODERATE SE TO S FLOW WILL PREVAIL SUN AND MON. SW N ATLC S OF 31N W OF 55W... A NEGATIVELY TILTED UPPER TROUGH FROM NEW ENGLAND TO ABOUT 500 NM NE OF BERMUDA IS SUPPORTING A WEAK COLD FRONT EXTENDING FROM THE N CENTRAL ATLC TO 31N60W THROUGH THE NORTHERN BAHAMAS AND SOUTH FLORIDA. AN ASCAT PASS FROM 1326 UTC INDICATED WINDS APPROACHING GALE FORCE N OF 30N WITHIN 120 NM EITHER SIDE OF THE FRONTAL BOUNDARY. BUOY 41007 NEAR 32N70W INDICATED SEAS TO 11 FT IN NW SWELL. 1020 MB HIGH PRES IS BUILDING EAST BEHIND THE FRONT OFF THE NE FLORIDA COAST...ALLOWING WINDS TO RAPIDLY DIMINISH W OF 70W. FRESH TO STRONG W TO NW FLOW N OF 24N E OF 70W WILL GRADUALLY DIMINISH FROM WEST TO EAST BEHIND THE EXITING FRONT. MEANWHILE...ANOTHER STRONGER FRONTAL SYSTEM WILL MIGRATE THROUGH THE EASTERN UNITED STATES THROUGH THU. S TO SW FLOW WILL INCREASE OFF THE NE COAST OF FLORIDA BY LATE THU AHEAD OF THE FRONT...REACHING BRIEFLY GALE FORCE BY EARLY FRI. THESE WINDS WILL SHIFT NW BEHIND THE FRONT AS IT PUSHES RAPIDLY EAST...REACHING FROM 31N75W TO THE STRAITS OF FLORIDA BY EARLY FRI...AND FROM 31N65W TO CENTRAL CUBA BY EARLY SAT. THE UPPER SUPPORT LIFTS MORE TO THE NE FRI INTO SAT...AND THE POTENTIAL FOR GALES DIMINISHES. NONETHELESS FRESH TO STRONG WINDS WILL PREVAIL BEHIND THE FRONT OVER THE ENTIRE AREA FRI AND SAT...THEN DIMINISH FROM WEST TO EAST SUN INTO MON...FOLLOWED BY SLOWLY SUBSIDING N SWELL TO 9 FT OUTSIDE OF THE BAHAMAS. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... GENTILE TO MODERATE BREEZES PERSIST OVER MOST OF THE CARIBBEAN BASIN AND TROPICAL N ATLC W OF 55W. THE EXCEPTION IS OFF THE COAST OF COLOMBIA WHERE AN ASCAT PASS FROM 1510 UTC INDICATED WINDS IN EXCESS OF 20 KT. THESE WINDS WILL INCREASE FURTHER FOR A BRIEF PERIOD TONIGHT AND THU AS HIGH PRES BUILDS N OF THE AREA. A COLD FRONT WILL PUSH THROUGH THE YUCATAN CHANNEL FRI...THEN SAG SOUTH ACROSS THE NW CARIBBEAN INTO SUN FOLLOWED BY FRESH TO STRONG NW FLOW. THE FRONT WILL WEAKEN AND STALL FROM ROUGHLY THE WINDWARD PASSAGE TO NE NICARAGUA BY SUN...AND WINDS WILL START TO DIMINISH OVER THE NW CARIBBEAN. WINDS WILL START TO INCREASE TO 20 TO 25 KT INTO MON OVER THE CENTRAL CARIBBEAN AS HIGH PRES BUILDS N OF THE AREA BEHIND THE FRONT. WAVEWATCH III AND ECWAVE OUTPUT INDICATES LONG PERIOD NORTHERLY SWELL WILL PUSH INTO THE WATERS NE OF THE LEEWARD ISLANDS STARTING FRI...EVENTUALLY DELIVERING SEAS OF 8 TO 11 FT TO THE ENTIRE TROPICAL N ATLC W OF 55W...AND PENETRATING THE ATLC PASSAGES INTO THE EASTERN CARIBBEAN WITH SEAS TO 8 FT BY SUN. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .GMZ011...GALE WARNING THU S OF 27N. .GMZ017...GALE WARNING THU W OF 95W. .GMZ011...GALE WARNING THU...THU NIGHT S OF 19N...GALE CONDITIONS EXPECTED EARLY FRI S OF 19N. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .AMZ111...GALE WARNING LATE THU NIGHT N OF 30N. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER CHRISTENSEN