000 AGXX40 KNHC 090734 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 334 AM EDT MON APR 9 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A 0338 UTC ASCAT PASS INDICATED A N-S ORIENTED SURFACE TROUGH ALONG 88W...BISECTING HIGH PRES THAT EXTENDS FROM THE LOWER MISSISSIPPI VALLEY TO THE SW GULF FROM HIGH PRES OVER THE ATLC NE OF THE BAHAMAS. ALTHOUGH SURROUNDING BUOYS ONLY SHOW 10 TO 15 KT NE WINDS...THE ASCAT PASS INDICATED THE PRESENCE OF 15 TO 20 KT OVER THE S CENTRAL GULF NEAR THE LOOP CURRENT AND TO THE EAST OF THE TROUGH. NO SIGNIFICANT SHOWER ACTIVITY IS NOTED CURRENTLY. GFS AND ECMWF GUIDANCE SHOW THE TROUGH DAMPENING OUT SLIGHTLY LATER TODAY AND COMING INTO TO PHASE WITH THE DIURNAL HEAT TROUGH THAT FORMS OVER THE YUCATAN...SOUTH OF WEAK HIGH PRES BUILDING OVER THE TEXAS COAST. THE FRESH E WINDS NOTED IN THE ASCAT PASS ARE EXPECTED TO DIMINISH AS THE TROUGH DEAMPLIFIES. MEANWHILE A VERY WEAK FRONT IS BECOMING QUASI-STATIONARY OVER THE NORTHERN GULF COAST THIS MORNING AND WILL START TO BECOME DIFFUSE THROUGH LATE TODAY. A SOMEWHAT MORE SUBSTANTIAL COLD FRONT WILL PUSH SOUTH THROUGH THE LOWER MISSISSIPPI VALLEY TONIGHT AND REACH THE NORTHERN GULF BY EARLY TUE. FRONTAL SYSTEMS TEND TO BE FAIRLY WEAK BY THIS TIME OF YEAR...AND THIS SECOND FRONT WILL MAKE ONLY SLOW PROGRESS SOUTHWARD INTO THE GULF...REACHING FROM THE FLORIDA BIG BEND AREA TO THE MOUTH OF THE MISSISSIPPI RIVER BY LATE TUE AND FROM TAMPA FLORIDA TO SW LOUISIANA BY LATE WED...BEFORE BECOMING DIFFUSE OVER THE SE GULF BY LATE THU. HIGH PRES WILL BUILD SOUTHWARD THROUGH THE LOWER MISSISSIPPI VALLEY AND INTO THE N CENTRAL GULF BEHIND THE WEAKENING FRONT. BOTH THE GFS AND ECMWF SHOW SE RETURN FLOW WILL INCREASE OVER THE FAR NW GULF THU. MODEL CONSENSUS SHOWS THE HIGH PRES SHIFTING EAST INTO THE CAROLINAS LATE THU AHEAD OF LOW PRES DIGGING INTO THE CENTRAL PLAINS...ALLOWING FRESH E TO SE WINDS ACROSS THE ENTIRE WESTERN GULF OF MEXICO FRI. CARIBBEAN SEA AND TROPICAL ATLC S OF 19N W OF 55W... 1022 MB HIGH PRES IS SETTLING N OF THE AREA BETWEEN THE NORTHERN BAHAMAS AND BERMUDA. THIS IS ENHANCING TRADE WIND FLOW TO THE SOUTH OF THE HIGH PRES AND LATEST SHIP OBSERVATIONS AND AN ASCAT PASS FROM 0156 UTC SHOW 20 TO 25 KT NE WINDS PUSHING THROUGH THE WINDWARD PASSAGE. WINDS TO 20 KT WILL FILTER ACROSS WESTERN AND CENTRAL CUBA EARLY THIS MORNING AND PUSH INTO THE WATERS WITHIN 120 NM ON THE SOUTH SIDE OF CUBA. GIVEN THE RELATIVELY LIMITED FETCH AND DURATION AS WELL MOSTLY SHALLOW WATERS WITHIN 60 NM OF THE COAST...MAXIMUM SIGNIFICANT WAVE HEIGHTS WILL BE LESS THAN 5 FT THROUGH TONIGHT. HIGH TERRAIN OVER FAR SE CUBA WILL BLOCK MUCH OF THIS WIND GETTING INTO THE AREA BETWEEN CUBA AND JAMAICA. ELSEWHERE WINDS ARE FAIRLY LIGHT FROM 55W ACROSS THE ISLANDS AND THROUGHOUT THE CARIBBEAN BASIN. BUOYS OVER THE CENTRAL AND NW CARIBBEAN HAVE BEEN REPORTING WINDS LESS THAN 10 KT AND SEAS AT 2 FT. THE HIGH PRES N OF THE AREA WILL SHIFT EASTWARD INTO THE CENTRAL ATLC AHEAD OF A COLD FRONT MOVING THROUGH THE SOUTHERN UNITED STATES TONIGHT AND TUE. THIS SHIFT WILL MAINTAIN THE LIGHT FLOW ACROSS THE CENTRAL AND WESTERN CARIBBEAN. A TIGHTER PRES GRADIENT SOUTH OF THE HIGH PRES WILL ALLOW E TRADES TO INCREASE IN THE TROPICAL N ATLC WATERS S OF 19N W OF 55W TUE THROUGH FRI. MEANWHILE DECAYING N SWELL OVER THE ATLC WATERS S OF 25N W OF 55W IS PUSHING TOWARD TROP N ATLC WATERS NE OF THE LEEWARD ISLANDS...AND THE ATLC PASSAGES TO THE NE CARIBBEAN. N SWELL OF 5 TO 7 FT WILL PUSH TO THE EAST OF THE LEEWARDS THROUGH TONIGHT...AND N SWELL OF 5 TO 6 FT PENETRATING THE MONA AND ANEGADA PASSAGES. EVEN AS THIS N SWELL SUBSIDES BELOW 5 FT BY LATE TUE...FRESH NE TO E SWELL WILL ENTER THE MIX IN THE WATERS S OF 15N E OF THE WINDWARD ISLANDS GENERATED BY A LONG FETCH OF 20 KT TRADE WINDS. WAVE ENSEMBLE OUTPUT SHOWS MAXIMUM SEA HEIGHTS REACHING 8 TO 9 FT AT BUOY 41101 E OF BARBADOS THU AND FRI. SOUTHWEST N ATLC FROM 19N TO 31N W OF 55W... 1022 MB HIGH PRES CENTERED NEAR 29N74W WILL SHIFT FURTHER EAST TO 29N62W TONIGHT AND WEAKEN SLIGHTLY BEFORE SHIFTING INTO THE N CENTRAL ATLC BY MID WEEK. S OF THE HIGH PRES...LATEST ASCAT...BUOY AND SHIP DATA SHOW A BAND OF 20 TO 25 KT TRADES SOUTH OF 25N. BUOYS ALSO SHOW A RIBBON OF N SWELL WITH SEAS OF 6 TO 9 FT PROPAGATING SOUTHWARD S OF 25N. THIS WILL GRADUALLY DECAY BELOW 8 FT THROUGH TONIGHT. A WEAK FRONTAL BOUNDARY WILL EXTEND E-W TO THE NORTH OF THE AREA OFF THE GEORGIA COAST TODAY...THEN BECOME DIFFUSE WITH LITTLE IMPACT ON THE MARINE WEATHER N OF 25N. SW WINDS N OF 27N W OF 70W WILL INCREASE TO 20 KT BY MIDWEEK AHEAD OF A SLIGHTLY STRONGER COLD FRONT THAT WILL GLIDE INTO THE WATERS N OF THE NORTHERN BAHAMAS AND E OF NE FLORIDA BY LATE WED FOLLOWED BY FRESH NW FLOW. THE FRONT WILL REACH FROM 31N73W TO E CENTRAL FLORIDA BY LATE WED. WINDS WILL DIMINISH BOTH AHEAD AND BEHIND THE FRONT BY LATE THU AS IT EXTENDS FROM 31N62W TO 25N70W TO S FLORIDA BY WITH A PRE FRONTAL TROUGH EXTENDING THROUGH THE MONA PASSAGE. GFS AND ECMWF GUIDANCE SHOWS THE FRONT WILL WEAKEN AS IT REACHES FROM 31N55W TO THE WINDWARD PASSAGE BY LATE FRI. HIGH PRES WILL BUILD BEHIND THE FRONT OFF THE GEORGIA COAST BY LATE FRI...ALLOWING NE TRADES TO INCREASE S OF 24N. 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