000 AGXX40 KNHC 231907 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 306 PM EST TUE MAR 23 2010 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W GULF OF MEXICO... A 1020 MB HIGH HAS SHIFTED INTO THE CENTRAL GULF TODAY... ALLOWING 20-25 KT S-SE RETURN FLOW TO DEVELOP ALONG THE MEXICAN COAST TO OFFSHORE OF BROWNSVILLE...PER A 1540 UTC ASCAT PASS. NO OBSERVATIONS AVAILABLE TO VERIFY WAVE HEIGHTS...BUT SHOULD BE APPROACHING 6 FT...AND RISING. WINDS ACROSS THE NE GULF HAVE DROPPED BELOW 15 KT FROM THE NW TO N...BUT SEAS STILL LINGERING AROUND 6 FT WELL OFFSHORE OF TAMPA AND INTO THE BIG BEND REGION. AS THE HIGH SLIDES NE OVERNIGHT THROUGH WED AND MOVES ACROSS N FLORIDA AND INTO THE ATLC...FLOW WILL OPEN UP ACROSS THE W AND SW HALVES OF THE GULF...YIELDING 20-25 KT S-SE FLOW W OF 90W BY 1200 UTC WED...WITH SEAS BUILDING 7 TO 9 FT ACROSS THE NW QUARTER OF THE GULF THROUGH THE AFTERNOON. THE NEXT FRONTAL SYSTEM WILL MOVE INTO THE NW GULF ON THU. A CUT OFF LOW CURRENTLY MOVING IN OFF THE PACIFIC AND ACROSS NORTHERN BAJA CALIFORNIA WILL MERGE WITH THE TROUGHING OVER THE PACIFIC NW CUT OFF FROM THE MAIN NORTHERN STREAM JET. LOOK FOR THE TWO TO ATTEMPT TO PHASE OVER THE SOUTHERN PLAINS ON WED WITH THE RESULTING TROUGH TURNING NEGATIVE TILT ALOFT OVER THE MISSISSIPPI VALLEY THU. THE GFS AND ECMWF NEVER FULLY PHASE THESE TWO SYSTEMS. AS A RESULT...THE SURFACE SYSTEM IS WEAKER THAN THE SYSTEM THAT SWEPT THROUGH THE GULF OVER THE WEEKEND AND GALES ARE NOT EXPECTED. THE LONGWAVE PATTERN IS EXPECTED TO BECOME INCREASINGLY LESS AMPLIFIED AND MORE PROGRESSIVE WED THROUGH SAT NIGHT...WITH A WLY SUB TROPICAL JET FORECAST TO PREVAIL ACROSS THE N HALF OF THE GULF. THE GFS HAS TRENDED TOWARD THE CONSISTENTLY FASTER ECMWF WITH THIS NEXT FRONTAL SYSTEM...AND ARE NOW VERY CLOSE IN TIMING. BOTH MODELS TAKE THE COLD FRONT FROM THE NE GULF TO THE YUCATAN PENINSULA BY FRI AFTERNOON AND THEN CARRY THE NORTHERN PORTION OF THE FRONT QUICKLY INTO THE ATLC SAT WHILE THE PORTION OVER THE SOUTHERN GULF DISSIPATES. TROPICAL ATLC E TO 55W AND CARIBBEAN SEA... A COLD FRONT EXTENDS FROM THE W CENTRAL ATLC NEAR 31N69W THROUGH E CUBA NEAR 21N77W THEN SW INTO THE W CARIB TO ALONG THE NICARAGUA COAST...WHERE ELY TRADES SPREADING WWD ARE PUSHING THE FRONT INLAND ACROSS NICARAGUA. A LARGE 1034 MB HIGH ACROSS THE CENTRAL ATLC IS PRODUCING A DECENT PRES GRADIENT ACROSS THE TROPICAL ATLC YIELDING A BROAD ZONE OF 20-25 KT NELY TRADES FROM 40W WWD INTO THE E CARIB...WITH SEAS 8-9 FT. INSIDE THE CARIB... N-NE FLOW TO AROUND 20 KT CAN BE FOUND WITHIN ABOUT 120 NM W OF THE FRONT AND SHOULD GRADUALLY VEER NE OVERNIGHT AND DIMINISH SLIGHTLY. THE REMAINDER OF THE BASIN IS UNDER FRESH TRADES WITH A 1402 UTC ASCAT PASS REVEALING 25 KT TRADES ACROSS THE CENTRAL CARIB EXTENDING N TO 16N AND WITH 25-30 KT OFF THE COLOMBIA COAST. THE TRADES ACROSS THE CARIB WILL STAY UP THROUGH THU AS THE HIGH SHIFTS E ACROSS N FLORIDA...WITH WINDS IN THE W CARIB VEERING NE TO E WED AT 15-20 KT...AND THEN E TO SE WED NIGHT AND THU AHEAD OF THE APPROACHING GULF FRONT. MEANWHILE...TRADES RELAX ACROSS THE ATLC AS THE CENTRAL ATLC HIGH MOVES E. SW N ATLC W OF 65W... COLD FRONT MENTIONED ABOVE EXTENDING THROUGH E CUBA...WITH SECONDARY FRONTAL TROUGH ACROSS THE NW PORTIONS SW TO THE NW BAHAMAS. LATE MORNING ASCAT PASSES SHOWED SLY FLOW OF 20-25 KT AHEAD OF THE FRONT N OF 25N AND 20-25 KT WLY FLOW BEHIND THE SECONDARY FRONTAL TROUGH. THIS WILL ALL LIFT OUT TO THE NE THROUGH WED EVENING WITH THE HIGH SLIDING INTO THE AREA OFF OF N FLORIDA...AND NE TO E TRADES RETURNING TO THE SE BAHAMAS AND THROUGH THE STRAITS. SLY FLOW WILL INCREASE ACROSS W PORTIONS OF THE AREA THU AFTERNOON THROUGH FRI AS THE PRES GRADIENT BUILDS BETWEEN THE HIGH TO THE E AND THE SYSTEM TRAVERSING THE GULF OF MEXICO TO THE W. THE FORECAST CALLS FOR THE COLD FRONT TO ENTER FAR NW WATERS FRI NIGHT AND QUICKLY TREK E THROUGH THE N PORTION OF THE FORECAST AREA ON SAT. WARNINGS... ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER STRIPLING