000 AGXX40 KNHC 131911 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 210 PM EST TUE DEC 13 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... HIGH PRES CENTERED OVER THE SE U.S. WILL COMBINE WITH THE PERSISTENT TROUGHING ALONG 64/65W TO MAINTAIN MODERATE TO FRESH NE-E WINDS ACROSS MOST OF THE GULF...EXCEPT FOR SELY FLOW W OF 93W. THE HIGH WILL SHIFT TO THE NE THROUGH MID WEEK ALLOWING FOR SOUTHERLY RETURN FLOW TO SET UP AT FIRST IN THE NW GULF...THEN SPREADING TO ACROSS ALL OF THE GULF WATERS BY WED NIGHT. THE STRONGEST WINDS WILL BE IN THE SE GULF NEAR THE STRAITS OF FLORIDA WITH WINDS TO 25 KT AND SEAS TO 9 FT THIS EVENING THROUGH WED NIGHT. A COLD FRONT WILL REACH THE TEXAS COAST FROM THE NW THU NIGHT AND PUSH JUST A FEW DEGREES E OFF THE UPPER MEXICAN COAST WHILE STALLING ACROSS S LOUISIANA THROUGH FRI...THEN PUSH S ALONG THE N GULF COAST...FROM BIG BEND REGION TO BROWNSVILLE BY SAT EVENING. FRESH N TO NE FLOW ACROSS NW GULF BEHIND FRONT WILL RAISE SEAS TO 6 FT ACROSS THE TEXAS COASTAL WATERS. ECMWF AND GFS NOW MORE INLINE WITH THIS FRONTAL TIMING AND MOVEMENT. CARIBBEAN SEA AND TROPICAL N ATLC... A TIGHTENING PRES GRADIENT WILL PREVAIL NEXT FEW DAYS OVER THE NW CARIBBEAN BETWEEN HIGH PRES TO THE N AND LOW PRES ACROSS NRN S AMERICA AND THE PERSISTENT TROUGH ALONG 64/65W. A 1500 UTC ASCAT PASS SHOWED N-NE WINDS 20-25 KT ACROSS THE FAR NW CARIB AND DOWNWIND OF WINDWARD PASSAGE. THE HIGH WILL SHIFT NE IN ADVANCE OF FRONTAL SYSTEM APPROACHING TEXAS COAST BY THU... AND TIGHTEN THE GRADIENT AGAINST THE PERSISTENT ELONGATED TROUGHING...ALLOWING FOR FRESH WINDS TO SPREAD TO ALL BUT THE EXTREME SE CARIBBEAN WATERS...INCREASING TO STRONG NEAR THE WINDWARD PASSAGE...AND IN THE LEE OF CUBA AND THE MONA PASSAGE. THE GRADIENT WILL WEAKEN SLIGHTLY IN THE NW CARIBBEAN BY FRI WITH WINDS DIMINISHING SLIGHTLY THERE AS A RESULT. MEANWHILE...THE TAIL END OF A SURFACE TROUGH LINGERS IN THE FAR NORTHERN TROPICAL N ATLC WATERS. THIS FEATURE WILL SLOWLY DRIFT E TO 55W BY LATE WED NIGHT AS A REINFORCING COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL MOVE INTO THE NW PORTION LATE WED NIGHT WITH FRESH N-NE WINDS BEHIND IT...AND SEAS BUILDING TO 10-11 FT IN NE SWELL. THE FRONT WILL REACH ALL THE WAY TO 15N BY LATE FRI WHERE IT IS FORECAST TO DEGENERATE INTO A SHEAR LINE WHILE STALLING OUT. STRONG LLVL FORCING WILL ALLOW FOR SIGNIFICANT RAINS ACROSS THE ISLANDS AS THE FRONT MOVES SLOWLY SE. SOUTHWEST N ATLC S OF 31N W OF 55W... A COMPLEX LOW LEVEL TROUGH PERSISTS ACROSS E PORTIONS OF THE AREA...FROM NEAR 31N63W TO 26N64W TO 21N62W THIS AFTERNOON. REINFORCING COLD AIR HAS ALREADY BEGUN TO SPILL INTO THE SW N ATLC TO THE W OF THE TROUGH...WITH FRESHENING N TO NE FLOW TO DOMINATE MOST OF THE AREA...MINUS NW PORTIONS...THROUGH THU. SHORTWAVE MOVING AWAY FROM ATLC COAST NOW TO NEAR 70W IS FORECAST TO INITIATE CYCLOGENESIS INVOF 35/36N56W OVERNIGHT...WITH GALES EXPECTED TO DEVELOP ACROSS N PORTIONS OF THE HSF AREA BETWEEN 53W AND 59W. DEEP LAYERED TROUGHING ACROSS THE NW ATLC WILL THEN MOVE SE...FORCING THE PERSISTENT LLVL TROUGHING ACROSS THE DISCUSSION AREA SE...AND ALLOWING A SERIES OF FRONTAL BOUNDARIES TO MOVE SE THROUGH THE DISCUSSION AREA. EXPECT FRESH TO STRONG N-NE WINDS AND SEAS 8 TO 11 FT WITH ISOLATED AREAS TO 12 FT ACROSS THE WATERS NE OF THE BAHAMAS THROUGH WED...BEFORE WINDS ABATE SLIGHTLY N OF 26N...AND A SECONDARY STRONG PULSE OF N-NE SWELL PROPAGATES ACROSS THE AREA DURING THE REMAINDER OF THE WEEK. STRONG NELYS THROUGH THE BAHAMAS WILL BUILD SEAS SW OF THE ISLANDS TO 6 TO 9 FT NEXT FEW DAYS. WARNINGS... 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 STRIPLING