000 AGXX40 KNHC 201957 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 200 PM EST THU DEC 20 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 STRONG COLD FRONT IS PUSHING RAPIDLY INTO THE NW GULF OF MEXICO THIS AFTERNOON...AND WILL REACH A POSITION FROM THE FLORIDA BIG BEND AREA IN THE NE GULF TO THE CENTRAL BAY OF CAMPECHE IN THE SW GULF BY TONIGHT. THE FRONT IS ASSOCIATED WITH A COMPLEX LOW PRES SYSTEM MOVING INTO THE MISSISSIPPI VALLEY...AND WILL SWEEP ACROSS THE ENTIRE GULF THROUGH EARLY FRI. THE COMBINATION OF A TIGHT PRES GRADIENT IN THE LOWER LEVELS OF THE ATMOSPHERE ALONG WITH STRONG COLD AIR ADVECTION IS RESULTING IN STRONG TO GALE FORCE WINDS BEHIND THE FRONT. SCATTEROMETER AND BUOY DATA SHOW WINDS REACHING GALE FORCE BEHIND THE FRONT OVER THE NW GULF SO FAR TODAY. WINDS TO GALE FORCE WILL FUNNEL ALONG THE HIGH TERRAIN OF THE VERACRUZ COAST THROUGH THE REMAINDER OF TODAY AND TONIGHT...WITH GALES PERSISTING IN THE FAR SW GULF INTO EARLY FRI. A LINE OF SHOWERS AND TSTMS IS FORMING AHEAD OF THE FRONT OVER THE NE GULF. WHILE GRADIENT FLOW MAY NOT REACH GALE FORCE OVER THE NE GULF THROUGH TONIGHT...GUSTS TO GALE FORCE ARE POSSIBLE GIVEN THE PUSH OF COLD AIR. COOL WATER OVER THE NORTHERN GULF AND THE LACK OF UPPER FORCING BEHIND THE FRONT MAY INHIBIT THE FREQUENCY OF GUSTS SOMEWHAT HOWEVER THROUGH TONIGHT AS THE COOLER AIR MOVES OVER THE AREA. WINDS AND SEAS DIMINISH FROM NW TO SE FROM LATE FRI INTO SUN AS HIGH PRES BUILDS BEHIND THE FRONT FROM W TO E ACROSS THE NORTHERN GULF...LEAVING GENERALLY GENTLE TO MODERATE BREEZES BY LATE WEEKEND IN MOST AREAS. MOSTLY MODERATE TO OCCASIONALLY FRESH SE TO S RETURN FLOW WILL INCREASE OVER THE NW GULF STARTING MON. A WEAK FRONT WILL MOVE OFF THE TEXAS COAST TUE. SW N ATLC S OF 31N W OF 55W... LATEST SHIP AND BUOY OBSERVATIONS INDICATE 15 TO 20 KT SE TO S FLOW OFF NE FLORIDA...INCREASING BETWEEN 1020 MB HIGH PRES EXITING TO THE EAST...AND A FRONTAL BOUNDARY CHARGING THROUGH THE DEEP SOUTH STATES AND GULF OF MEXICO. THE FRONT WILL MOVE OFF THE SOUTHEAST COAST OF THE UNITED STATES ON WINDS TO GALE FORCE CAN BE EXPECTED TONIGHT IN THE SW FLOW AHEAD OF THE FRONT. STRONG COLD AIR ADVECTION BEHIND THE FRONT WILL RESULT IN UNSTABLE CONDITIONS OVER THE WARMER GULF STREAM WATERS OFF NE FLORIDA...ALLOWING FOR FREQUENT GUSTS TO GALE FORCE N OF 30N INTO EARLY FRI. THE FRONT WILL SWEEP SE AND EXTEND FROM 31N65W TO CENTRAL CUBA BY EARLY SAT...AND FROM 31N57W TO THE WINDWARD PASSAGE BY EARLY SUN. STRONG W TO NW WINDS FOLLOW THE FRONT ACROSS THE REGION WITH SEAS BUILDING TO 15 FT IN THE WATERS N OF 27N. THE AIRMASS BEHIND THE FRONT WILL MODIFY AS IT SHIFTS SE AND STRONG HIGH PRES WILL BUILD INTO THE WATERS BETWEEN NE FLORIDA AND BERMUDA THROUGH EARLY NEXT WEEK. WINDS WILL VEER MORE NE AND DIMINISH THROUGH SUN. SEAS WILL SUBSIDE FROM WEST TO EAST ACCORDINGLY ALTHOUGH LINGERING NORTHERLY SWELL OF 8 TO 12 FT WILL PERSIST ACROSS THE WATERS OUTSIDE OF THE BAHAMAS THROUGH MON. GENTLE TO MODERATE BREEZES PREVAIL N OF 22N BY TUE...WITH MODERATE TO FRESH TRADES PREVAILING S OF 22N. CARIBBEAN SEA AND TROPICAL N ATLC S OF 22N W OF 55W... GENTLE TO MODERATE BREEZE CONTINUES OVER MOST OF CARIBBEAN BASIN AND TROPICAL N ATLC W OF 55W...EXCEPT ALONG COAST OF COLOMBIA FROM 70W TO 80W WHERE INCREASING FRESH ELY BREEZES PERSIST WITH SEAS BUILDING TO 10 FT. WINDS LIKELY WILL INCREASE FURTHER FOR A BRIEF PERIOD TODAY AS HIGH PRES BUILDS N OF AREA. COLD FRONT PUSH THROUGH YUCATAN CHANNEL FRI THEN STALL ACROSS NW CARIBBEAN SUN FROM WINDWARD PASSAGE TO NE NICARAGUA BY SUN AND WINDS DIMINISH OVER NW CARIBBEAN. WINDS INCREASE AGAIN MON OVER CENTRAL CARIBBEAN AS HIGH PRES BUILDS N OF AREA BEHIND FRONT. NOTE...GRIDDED MARINE FORECAST IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE GULF OF MEXICO... .GMZ011...GALE WARNING S OF 27N. .GMZ013...GALE WARNING S OF 27N. .GMZ017...GALE WARNING W OF 95W. .GMZ011...GALE WARNING S OF 27N. .GMZ023...GALE WARNING TONIGHT S OF 21N. CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. SW N ATLANTIC... .AMZ111...GALE WARNING THU NIGHT N OF 30N. .AMZ113...GALE WARNING THU NIGHT N OF 30N. .AMZ115...GALE WARNING THU NIGHT N OF 30N. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER CHRISTENSEN