000 AGXX40 KNHC 121945 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 245 PM EST SAT MAR 12 2011 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... THE 1800 UTC PRELIMINARY SURFACE ANALYSIS REVEALS A 1028 MB HIGH CENTERED INLAND THE BIG BEND OF FLORIDA WITH A RIDGE W TO NE TEXAS. LATEST BUOY OBSERVATIONS FROM ACROSS THE GULF REVEAL GENERALLY LIGHT SE TO S WINDS W OF ABOUT 87W...AND LIGHT NE TO E WINDS E OF 87W WITH THE EXCEPTION OF THE FAR SE WATERS WHERE A SLIGHTER STRONGER GRADIENT IS ALLOWING FOR NE TO E WINDS OF 10-15 KT...AND ALONG THE NORTHERN YUCATAN PENINSULA WHERE GEOGRAPHY INDUCED GRADIENT IN THE OVERNIGHT HOURS BRINGS NE-E WINDS OF 15-20 KT NEAR THAT COAST. SEA STATE ANALYSIS FROM THROUGHOUT THE MORNING SHOWED RATHER LOW SEAS OVER MUCH OF THE GULF...EXCEPT IN THE FAR WESTERN PORTION NEAR THE TEXAS COAST WHERE A STRONGER S RETURN FLOW OF 15-20 KT HAS BUILD SEAS UP TO 7 FT AS REPORTED BY BUOY 42020 AT 27N97W. THE HIGH CENTER WILL SHIFT E TO ACROSS NORTHERN FLORIDA TONIGHT AND SUN ALLOWING FOR THE SE TO S WINDS TO EXPAND SOME EASTWARD. MODELS SUGGEST THAT A WEAK COLD FRONT WILL APPROACH THE FAR NW GULF SECTION EARLY MON...THEN MOVE ACROSS THE NORTHERN AND CENTRAL PORTIONS LATER ON MON AND TUE...AND REACH THE FAR NE WATERS BY LATE TUE BEFORE WEAKENING AS IT MOVES ACROSS FLORIDA EARLY WED. WINDS OVER THE EASTERN GULF N OF 27N WILL BECOME SE-S 5 KT KT EARLY ON MON THEN SHIFT TO SW IN THE AFTERNOON AHEAD OF THE APPROACHING COLD FRONT. BEHIND THE FRONT PRESENTLY IT APPEARS THE FLOW WILL BE LIGHT WITH NW WINDS OF 5 KT EXPECTED ON WED...AND SEAS ONLY AT 1 FT AT THE MOST AS A WEAK PRESSURE PATTERN BECOMES ESTABLISHES OVER THE GULF DURING WED. ON THU...A HIGH BECOMES LOCATED SITUATED AGAIN OVER THE FAR NE GULF WITH ITS INFLUENCES TO BE SEEN AS BRINGING BACK AN E-SE LIGHT WIND REGIME ACROSS THE AREA. WAVEWATCH MODEL GUIDANCE ARE IN VERY GOOD AGREEMENT THAT SEAS WILL BE LOW DURING THE EARLY TO MID PART OF NEXT WEEK. CARIBBEAN SEA AND TROPICAL N ATLC W OF 55W... THE SOUTHERN PORTION OF THE ATLC COLD FRONT THAT PREVIOUSLY HAD REACHED EASTERN CUBA AND NE HONDURAS HAS SINCE DISSIPATED AS HIGH PRES RIDGES SE ACROSS THE NW CARIBBEAN SEA. JUST RECENTLY RECEIVED HIGH RESOLUTION ASCAT DATA FROM 1816 UTC THIS AFTERNOON SHOWED A SWATH OF NE 20 KT WINDS INFILTRATING THROUGH THE WINDWARD PASSAGE...AND PUSHING INTO THE EASTERN PORTION OF THE NW CARIBBEAN TO AS FAR S AS 17N. AN 18 UTC NE 20 KT OBSERVATION BY SHIP "DGAF" NEAR 17.5N75W CAME IN WITH A NE 20 KT. THIS CORROBORATES WELL WITH THE ASCAT DATA. ANOTHER ASCAT PASS FROM JUST PASS 13 UTC THIS MORNING REVEALED NE WINDS OF 15-20 KT OVER THE NE PORTION OF THE CARIBBEAN. ASIDE FROM THESE TWO GENERAL AREAS OF THE CARIBBEAN AND THAT NEAR THE COAST OF COLOMBIA WHERE SHIP "C6KD7" REPORTED NE 20 KT WINDS THIS MORNING...THE REMAINDER OF THE CARIBBEAN ALONG WITH THE TROPICAL N ATLC ZONE REMAIN UNDER A MODERATE NE BREEZE. AS THE HIGH PRES N OF THE AREA CONTINUES TO BUILD E...EXPECT LITTLE OVERALL CHANGES TO THE ABOVE DESCRIBED 20 KT WIND AREAS. WINDS...HOWEVER...ARE EXPECTED TO INCREASE TO 20-25 KT IN THE SW CARIBBEAN SEA BEGINNING LATE TUE...AND INCREASE IN AREAL COVERAGE LATE WED AFTERNOON INTO THU AS IT MERGES WITH THE SIMILAR WINDS THAT EXPAND S AND SW TO THE S OF HISPANIOLA AS THE PRES GRADIENT ON THE SOUTHERN PERIPHERY OF THE ATLC HIGH TIGHTENS. THE MODERATE NE BREEZE ACROSS THE TROPICAL N ATLC SHOULD BEGIN TO INCREASE TO 20 KT DURING THU IN RESPONSE TO THE TIGTHEN OF THE PRES GRADIENT. N SWELLS OF UP TO 8 FT AS REPORTED BY BUOY 41044 NEAR 22N59W WILL SLOWLY SUBSIDE THROUGH EARLY MON. ANOTHER BATCH OF N SWELLS...POSSIBLY PRODUCING SEAS UP TO 8 FT...IS EXPECTED TO APPROACH THE FAR NW TROPICAL N ATLC ON THU. SW N ATLC... THE 1800 UTC PRELIMINARY SURFACE ANALYSIS ALONG WITH VISIBLE SATELLITE IMAGERY REVEALS A COLD FROM NEAR 31N64W STRETCHING SW TO THE FAR SE BAHAMA ISLANDS. BUOYS 41047 NEAR 27.5N71W AND BUOY 41046 NEAR 24N71W ARE REPORTING N-NE WINDS OF 15-20 KT EARLY THIS AFTERNOON...WITH SEAS IN THE 7-9 FT IN A NE SWELL. ELSEWHERE W OF THE FRONT WINDS HAVE DIMINISHED TO NW-N 10 KT...EXCEPT S OF 26N WHERE A LINGERING TIGHTER PRES GRADIENT IS ALLOWING FOR NE WINDS OF 10-15 KT. NE WINDS OF 20 KT ARE OCCURRING OVER THE AREA BETWEEN THE SE BAHAMAS AND HAITI...AND THROUGH THE WINDWARD PASSAGE. THE 1512 UTC ASCAT PASS FROM THIS MORNING CAPTURES THESE WINDS PRETTY WELL WHEN COMPARED TO MODEL WIND GUIDANCE. WINDS E OF THE FRONT ARE LIGHT MAINLY NE-E EXCEPT N OF 25N WHERE ASCAT DATA FROM 1332 UTC DEPICTED LIGHT AND VARIABLE WINDS. HOWEVER...NE SWELLS RESULTING IN COMBINED SEAS OF UP TO 8 OR 9 FT AND PERIODS OF 10-12 SEC WILL CONTINUE TO MIX WITH SHORTER PERIOD NW-N SWELLS OVER THE FAR EASTERN PORTION INTO LATE SUN NIGHT AND EARLY MON MORNING. THE SYNOPTIC 1800 UTC PRELIMINARY ANALYSIS HAS HIGH PRES RIDGING FROM THE NE GULF OF MEXICO EASTWARD TO ALONG 30N BEHIND THE FRONT. THE FRONT WILL BEGIN TO WEAKEN AS IT REACHES A PSN FROM NEAR 28N65W TO WINDWARD PASSAGE TONIGHT...THEN GRADUALLY DISSIPATE AS IT MOVES ACROSS THE FAR SE PORTION SUN AND TO E OF AREA SUN NIGHT AND MON. HIGH PRES WILL MOVE E ACROSS NORTHERN FLORIDA THROUGH TONIGHT...AND E ALONG 30N THROUGH MON. THE HIGH WILL THEN SHIFT TO THE NE PORTION TUE AND WED IN RESPONSE TO A COLD FRONT THAT MOVES OFFSHORE THE SE U.S. COAST. GLOBAL MODELS ARE IN PRETTY GOOD AGREEMENT THAT THIS NEXT COLD FRONT WILL QUICKLY BRUSH THROUGH THE NORTHERN AND CENTRAL WATERS LATER ON WED INTO THU...AND REACH FROM NEAR BERMUDA TO NEAR 27N74W BY LATE THU AS THE SOUTHERN PORTION WILL MOST LIKELY WASH OUT AS HIGH PRES AGAIN BEGINS TO BUILD E ACROSS THE REGION. WINDS BEHIND THIS FRONT ARE EXPECTED TO BE NLY IN THE 15-20 KT RANGE. WARNINGS.. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER AGUIRRE