000 AGXX40 KNHC 110720 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 320 AM EDT WED APR 11 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... 1019 MB SURFACE HIGH PRES IS CENTERED OFF THE SW LOUISIANA COAST. A WEAK SURFACE TROUGH IS POSITIONED FROM 23N94W TO 19N91W IN THE BAY OF CAMPECHE. A 0250 UTC WINDSAT AND REPORTS FROM A BUOY 42056 IN THE SW GULF SHOW NE WINDS 15 TO 20 KT WITHIN 120 NM E OF THE TROUGH AND OFF THE NW COAST OF YUCATAN. RELATIVELY FLAT SEAS PERSIST ACROSS THE GULF THIS MORNING. BUOYS ARE REPORTING 1 TO 2 FT OVER THE NE GULF AND GENERALLY 2 TO 4 FT ELSEWHERE. THE PATTERN WILL START TO CHANGE TODAY AS AN UPPER DISTURBANCE PUSHES THROUGH THE CAROLINAS TODAY...WITH AN ASSOCIATED COLD FRONT PUSHING THROUGH THE SE STATES AND INTO THE NE GULF BY LATE TODAY. THE FRONT WILL EXTEND FROM 27N83W TO NEAR THE MISSISSIPPI RIVER DELTA BY LATE TODAY. THE FRONT WILL START TO BECOME DIFFUSE AS IT SAGS FURTHER SOUTH THU REACHING FROM SW FLORIDA TO SW LOUISIANA BY LATE THU. HIGH PRES WILL BUILD OVER THE EASTERN UNITED STATES BEHIND THE FRONT WED THROUGH FRI...AS LOW PRES MOVES INTO THE CENTRAL PLAINS STATES. THE GFS/ECMWF/UKMET CONSENSUS SHOWS THIS WILL SET UP A TIGHT ENOUGH PRES GRADIENT OVER THE WESTERN GULF TO SUPPORT 20 KT E TO SE WINDS BY THU NIGHT. FOR FRI AND SAT...THIS WILL BECOME SE WINDS 20 TO 25 KT OVER MOSTLY THE NW GULF...WITH E TO SE WINDS TO 20 KT ELSEWHERE. THE GFS REMAINS SLIGHTLY STRONGER THAN THE ECMWF BY SUN...SHOWING WINDS TO 25 KT ACROSS THE GULF WITH 30 KT OVER THE FAR NW GULF. THE FORECAST FAVORS THE MORE CONSERVATIVE ECMWF SHOWING MOSTLY 20 TO 25 KT FLOW. THE NWW3/FNMOC WAVE ENSEMBLE GUIDANCE INDICATES SEAS WILL BUILD AS HIGH AS 10 FT NEAR BUOY 42019...ABOUT 60 NM S OF FREEPORT TX BY EARLY SUN...WITH FRESH SE SWELL. CARIBBEAN SEA... BUOY/SHIP OBSERVATIONS ALONG WITH SCATTEROMETER DATA SHOW FAIRLY LIGHT WINDS AND SEAS ACROSS ALMOST THE ENTIRE BASIN...WITH THE EXCEPTION OF THE FAR EASTERN PORTION OF THE CARIBBEAN NEAR THE LESSER ANTILLES WHERE 15 TO 20 KT TRADE WIND FLOW IS EVIDENT ACROSS THE ISLANDS. THERE MAY STILL BE NE TRADES TO 20 KT SLIPPING THROUGH THE WINDWARD PASSAGE AND JUST ON THE LEE SIDE OF CUBA THIS MORNING AS WELL. THESE WINDS AHEAD OF A SURFACE TROUGH FROM HISPANIOLA TO 25N67W...AND SOUTH OF A RIDGE FROM THE CENTRAL ATLC THROUGH THE BAHAMAS. THESE WINDS WILL DIMINISH THIS MORNING AS THE HIGH PRES TO THE NORTH WEAKENS. THE RELATIVELY GENTLE CONDITIONS WILL PERSIST THROUGH THU. NE TRADES WILL START TO INCREASE STARTING FRI AGAIN THROUGH THE WINDWARD PASSAGE AS STRONG HIGH PRES BUILDS OFF THE CAROLINAS BEHIND A WEAK COLD FRONT THAT WILL SAG TO CUBA BY EARLY SAT. GFS AND ECMWF GLOBAL MODELS SHOW NE WINDS 20 TO 25 KT COVERING MOST OF THE CARIBBEAN N OF 15N BY LATE SAT...WITH THE STRONGEST WINDS PUSHING THROUGH THE WINDWARD AND MONA PASSAGES. BY SUN...THE ENTIRE BASIN WILL BE COVERED IN 20 KT NE TO E WINDS...WITH E TO SE WINDS OVER THE FAR NE CARIBBEAN. ENSEMBLE WAVE GUIDANCE SHOWS SEAS BUILDING TO 6 TO 8 FT BY SUN. TROPICAL NORTH ATLANTIC S OF 19N W OF 55W... A 1030 MB SURFACE HIGH IS CENTERED OVER THE N CENTRAL ATLC NEAR 36N39W...WITH A RIDGE EXTENDING TO A 1022 MB SURFACE HIGH NEAR 39N60W. THE RIDGING N OF THE AREA IS ALLOWING MAINLY 15 TO 20 KT FLOW ACROSS THE AREA E OF THE LEEWARD AND WINDWARD ISLANDS AS SHOWN BY BUOYS AND SCATTEROMETER. THE FRESH TRADE WIND FLOW WILL PERSIST THROUGH THU THEN DIMINISH AS THE RIDGING TO THE NORTH WEAKENS AHEAD OF AN COLD FRONT MOVING INTO THE AREA FROM THE WEST. WAVE ENSEMBLE GUIDANCE SHOWS SEAS PEAKING AROUND 9 FT AT BUOY 41011 ABOUT 270 NM EAST OF MARTINIQUE BY LATE THU AS NE SWELL WITH PERIODS AROUND 8 SECONDS PUSHES INTO THE AREA. BY SUNDAY...THE FRONT WILL STALL JUST N OF THE LEEWARD ISLANDS...BUT FRESH TO STRONG NE WINDS ACCOMPANIED BY SEAS OF 8 TO 10 FT AND SCATTERED SHOWERS WILL REACH THE NORTHERNMOST LEEWARDS HAS HIGH PRES BUILDS N OF THE AREA BEHIND THE DISSIPATING FRONT. SW NORTH ATLANTIC S OF 31N W OF 55W... A 1022 MB SURFACE HIGH IS CENTERED NEAR 30N60W WITH A RIDGE EXTENDING TO S FLORIDA. A SURFACE TROUGH EXTENDS FROM HISPANIOLA TO 25N67W. SHIP AND SCATTEROMETER DATA SHOW 20 KT NE TO E FLOW AHEAD OF THE TROUGH AND SOUTH OF THE RIDGE THROUGH THE SOUTHERN BAHAMAS AND TCI. A COUPLE OF SMALL CLUSTERS OF THUNDERSTORMS ARE NOTED NW OF THE RIDGE OFF THE COAST OF NE FLORIDA...WHERE WEAK DISTURBANCES IN THE BASE OF AN UPPER TROUGH ARE KEEPING WEATHER UNSETTLED OVER THE WARMER GULF STREAM WATERS. THE RIDGE WILL DISSIPATE TODAY AHEAD OF A COLD FRONT NOW OVER THE COASTAL SOUTHEAST UNITED STATES. THE FRONT WILL REACH FROM 31N73W TO CENTRAL FLORIDA BY LATE TODAY...FROM NEAR BERMUDA TO S FLORIDA EARLY THU. THE AIRMASS BEHIND THE FRONT WILL MODIFY RAPIDLY AS IT SHIFTS SOUTH...WITH THE EXTENDING FROM 31N62W TO THE STRAITS OF FLORIDA BY LATE THU AND FROM 31N55W TO EASTERN CUBA BY LATE FRI. THE MAIN WEATHER MAKER WILL BE THE HIGH PRES PUSHING OFF THE CAROLINA COAST BY FRI AFTERNOON BEHIND THE FRONT. THE GFS AND UKMET ARE SLIGHTLY STRONGER THE ECMWF...BUT THERE IS GENERALLY AGREEMENT IN POSITION AND STRENGTH OF THE HIGH PRES. THIS WILL ALLOW TRADE WINDS TO INCREASE MAINLY S OF 25N W OF 55W FRI THROUGH SUN BEHIND THE DYING FRONT. THE MEAN OF NWW3/FNMOC ENSEMBLE GUIDANCE SHOWS SEAS REACHING 9 FT IN THE ATLC WATERS JUST EAST OF THE SOUTHERN BAHAMAS BY SUNDAY. NOTE... EFFECTIVE APR 3, 2012 AT 1800 UTC THE OFFSHORE WATERS FORECAST ZONES CHANGED FOR THE CARIBBEAN AND SW N ATLANTIC AND THE GULF OF MEXICO. ISSUANCE TIME FOR THE GULF OF MEXICO OFFSHORE WATERS FORECASTS IS REFERENCED TO THE EASTERN TIME ZONE. FOR DETAILS SEE WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE). GULF OF MEXICO... .NONE. .CARIBBEAN SEA AND TROPICAL N ATLC... .NONE. .SW N ATLC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER CHRISTENSEN