000 AGXX40 KNHC 041801 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 200 PM EDT MON APR 04 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... WINDSAT AND ASCAT PASSES FROM THIS LATE MORNING/EARLY AFTERNOON SHOW SOUTHERLY RETURN FLOW OF 20-25 KT IN THE W GULF AND 15-20 KT IN THE E GULF AHEAD OF A COLD FRONT CURRENTLY LOCATED FROM SW ARKANSAS THROUGH CENTRAL TEXAS. THE FRONT WILL MOVE OFF THE TEXAS COAST AND INTO THE NW GULF EARLY THIS EVENING REACHING FROM S CENTRAL LOUISIANA TO NEAR THE TEXAS/MEXICO BORDER. SOUTHERLY RETURN FLOW LOOKS TO DIMINISH JUST AHEAD OF THE FRONT AS THE PRES GRADIENT WEAKENS AND WINDS VEER MORE S-SW. THE FRONT WILL MOVE E FROM THE FLORIDA BIG BEND TO THE CENTRAL BAY OF CAMPECHE TUE MORNING THEN WILL STALL AS IT REACHES FROM THE STRAITS OF FLORIDA TO ALONG THE YUCATAN COAST TUE EVENING. THE LATEST GFS AND ECMWF BOTH CONTINUE TO SHOW SOLID 25-30 KT NORTHERLY WINDS SURGING IN BEHIND THE FRONT. THE 12 UTC GFS ENSEMBLES HAVE LOWERED THE PROBABILITY OF GALE CONDITIONS TO AROUND 10 PERCENT WHILE THE SREF SHOWS LESS THAN 10 PERCENT ACROSS THE GULF BEHIND THE FRONT...EXCEPT THE W BAY OF CAMPECHE S OF 21N W OF 95W WHERE A 40 PERCENT CHANCE IS STILL PROGGED. HAVE ELECTED TO KEEP WINDS CAPPED AT NEAR GALE WHILE GALE FORCE CONDITIONS MAY OCCUR INSIDE THE COASTAL WATERS (0-60 NM FROM U.S. SHORE). REFER TO CWF PRODUCTS ISSUED BY LOCAL NWS OFFICES. THE SOUTHERN END OF THE FRONT WILL DISSIPATE IN THE FAR SE GULF TUE NIGHT WITH HIGH PRES QUICKLY BUILDING IN BEHIND IT. THE HIGH WILL SHIFT E INTO THE ATLC WED THROUGH FRI ALLOWING FOR SOUTHERLY RETURN FLOW TO DEVELOP...INCREASING FRI AS THE PRES GRADIENT TIGHTENS. CARIBBEAN SEA AND TROPICAL N ATLC... FRESH TO STRONG TRADES HAVE EXPANDED IN COVERAGE AS HIGH PRES HAS MOVED CLOSER TO THE AREA LOCATED IN THE SW N ATLC. THE STRONGER TRADES NOW EXTEND FROM THE E CARIBBEAN THROUGH THE CENTRAL CARIBBEAN AS INDICATED BY RECENT WINDSAT AND ASCAT SCATTEROMETER PASSES. TRADES WILL CONTINUE TO EXPAND ENCOMPASSING THE TROPICAL N ATLC AND GULF OF HONDURAS TONIGHT WITH WINDS UP TO 30 KT POSSIBLE NEAR THE COAST OF COLOMBIA WHERE SEAS WILL ALSO BUILD CLOSE TO 14 FT. MEANWHILE WINDS WILL VEER MORE TO THE SE-S IN THE NW CARIBBEAN TONIGHT AND TUE AS THE FRONT MOVES CLOSER TO THE AREA. TRADES WILL DIMINISH ACROSS THE BASIN TUE AFTERNOON THROUGH FRI AS A COLD FRONT IN THE GULF OF MEXICO APPROACHES THE YUCATAN CHANNEL. THE SOUTHERN END OF THE FRONT WILL DISSIPATE JUST NW OF THE AREA WHILE THE NORTHERN END WILL KEEP MOVING E THROUGH THE SW N ATLC...CONTINUING TO WEAKEN THE PRES GRADIENT ACROSS THE REGION FROM W TO E. SOUTHWEST N ATLC W OF 55W... THE TAIL END OF A COLD FRONT REACHES FROM 26N55W TO NEAR THE TURKS AND CAICOS EARLY THIS AFTERNOON. THE SOUTHERN PORTION OF THIS FRONT WILL DISSIPATE OVER THE AREA BY THE EVENING WHILE THE REST OF THE FRONT CONTINUES TO TREK TO THE E. LARGE NW SWELLS NEAR 15 FT CONTINUE TO IMPACT THE FAR NE CORNER OF THE AREA AND ARE EXPECTED TO QUICKLY DECAY TO 8 FT OR LESS BY TUE. 1025 MB HIGH PRES IS CENTERED NEAR 30N68W WITH A RIDGE AXIS EXTENDING ACROSS CENTRAL FLORIDA AND ACROSS THE N GULF OF MEXICO WATERS. A TIGHT PRES GRADIENT EXISTS OVER THE SOUTHERN WATERS AND RECENT WINDSAT AND ASCAT PASSES INDICATED NE-E 20-25 KT WINDS IN THAT AREA. MEANWHILE SOUTHERLY RETURN FLOW IS INCREASING E OF FLORIDA AHEAD OF THE NEXT COLD FRONT. THE FRONT WILL MOVE INTO THE FAR NW PART TUE AFTERNOON EXTENDING FROM 31N78W TO 29N80W WITH 20-25 KT NW WINDS BEHIND IT AND 20-30 KT WINDS N OF 27N AHEAD OF THE FRONT. THE FRONT WILL QUICKLY REACH FROM W OF BERMUDA TO THE SE BAHAMAS WED MORNING MOVING E OF THE AREA BY THU MORNING. HIGH PRES BUILDS BACK IN BEHIND THE FRONT LATE WED THROUGH FRI WITH WINDS DIMINISHING TO 10-15 KT AND VEERING TO THE E-SE AS THE HIGH SETTLES ACROSS THE NE PART OF THE AREA. SOUTHERLY RETURN FLOW BECOMES RE-ESTABLISHED LATE FRI INTO THE WEEKEND AS THE HIGH SLIDES MORE TO THE E. WARNINGS.. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER LEWITSKY