000 AGXX40 KNHC 191945 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 345 PM EDT THU MAR 19 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE REMNANTS OF AN OLD FRONTAL TROUGH ARE STRUNG OUT NEARLY W TO E ALONG ABOUT 90W FROM 21N TO 27N. NE-E WINDS OF 15-20 KT WERE NOTED BOTH ON QUIKSCAT DATA FROM THIS MORNING AND BY REPORTS FROM BUOY 42001 DURING THE MORNING AND AFTERNON. MARINE CONDITIONS ACROSS THE GULF ARE RELATIVELY TRANQUIL...ESPECIALLY ACROSS THE S HALF...WITH SEAS THERE 3 FT OR LESS. 4 FT SEAS WITH AREAS 5-6 FT ARE EXPECTED N OF 26N AND W OF 85W WHERE THIS STRONGER E TO NE WIND FLOW WILL PREVAIL...WITH HIGHER WIND AND SEAS POSSIBLE NEAR TSTMS. A DEEP LAYER TROUGH WILL SWEEP SE ACROSS THE NE AND ERN U.S. OVER THE NEXT 24 HRS...WITH AN ASSOCIATED COLD FRONT EXPECTED TO REACH THE NORTHERN GULF LATE TONIGHT AND EARLY FRI. STRONG HIGH PRESSURE WILL MOVE IN BEHIND THIS FRONT...AND N-NE WINDS SHOULD PICK UP FRI THROUGH THE WEEKEND OVER THE GULF....BUILDING SEAS 5 TO 6 FT IN NE WIND SWELL. BY MON AND TUE...THE NEXT DEEP LAYER TROUGH SHOULD MOVE INTO THE PLAINS...ENHANCING SOUTHERLY RETURN FLOW IN THE WESTERN GULF WHILE ELY FLOW INCREASES OVER MUCH OF THE SOUTHERN PORTIONS OF THE MIDDLE AND EASTERN GULF. CARIBBEAN SEAS... WINDS HAVE DIMINISHED ACROSS THE CARIBBEAN FROM RECENT DAYS WITH THE HIGHEST WINDS...TO 25 KT...CONTAINED ACROSS SW SECTIONS AND OFF THE COLOMBIAN COAST. THIS WEAKENED FLOW WILL CONTINUE AS HIGH PRES WELL NE OF THE CARIBBEAN WEAKENS AND SHIFTS FURTHER EAST AHEAD OF THE DEEP LAYER TROUGH MENTIONED ABOVE. HIGH PRES CURRENTLY OFF THE MID ATLC COAST WILL CONTINUE MOVING EASTWARD AND PASS N OF BERMUDA SHORTLY...AND ACT TO MAINTAIN MODERATE TRADE WINDS OVER THE EASTERN CARIBBEAN THROUGH THE WEEKEND. THE DEEP LAYERED TROUGH WILL PUSH THROUGH THE EASTERN U.S. DURING THE NEXT 24 HRS AND THEN INTO THE WRN ATLC...FOLLOWED BY STRONG SURFACE HIGH PRES BUILDING INTO THE GULF OF MEXICO/MID ATLC REGIONS. THIS WILL INCREASE THE PRESSURE GRADIENT OVER THE CARIBBEAN AND INCREASE WINDS ONCE AGAIN OVER 20 KT OVER MUCH OF THE WESTERN CARIBBEAN OVER THE WEEKEND...AND SPREAD INTO THE EASTERN CARIBBEAN MON AND TUE. ATLANTIC S OF 31N W OF 55W... A COLD FRONT EXTENDS FROM A DEEP 989 MB SURFACE LOW NE OF THE AREA TO 31N48W TO 24N65W AND THEN INTO THE NW BAHAMAS AND HAS BEEN MEANDERING ACROSS EXTREME SRN FLORIDA AND THE UPPER KEYS OVERNIGHT. THE DEEP LAYERED SURFACE LOW WILL MOVE FURTHER E-NE TODAY...ALLOWING HIGH PRES TO BUILD BEHIND IT OFF THE EASTERN SEABOARD. FRESH TO STRONG N-NE WINDS HAVE ALREADY DIMINISHED OVER THE WATERS BETWEEN N FLORIDA AND BERMUDA...BUT THE NELY WIND SWELL WILL CONTINUE TO AFFECT THE WATERS N THROUGH NE OF THE BAHAMAS AND PUSH THROUGH THE DEEPER GAPS TODAY. LARGE NNW SWELL IS EXPECTED TO PROPAGATE S AND SE...WITH PEAK ENERGY EXPECTED TO JUST MISS THE ERN CARIBBEAN ISLANDS TO THE EAST THROUGH SAT. HOWEVER...TWO PULSES OF LONG PERIOD SWELL...PEAKING AT 2.0-2.5 METERS...ARE FORECAST BY WWIII TO AFFECT THE ATLC WATERS OF THE NE AND E CARIB FRI THROUGH SUN...AND PROPAGTE THROUGH THE GAPS AND PASSAGES AND INTO THE CARIBBEAN. AS THIS MAJOR LONG WAVE TROUGH PUSH OFF THE EASTERN U.S. TONIGHT WITH A STRONG SW JET ALOFT AHEAD OF THE TROUGH...DIVERGENT FLOW ALOFT ON THE RIGHT REAR FLANK OF THE JET WILL SUPPORT THE DEVELOPMENT OF A WEAK SURFACE TROUGH JUST EAST OF THE BAHAMAS. AS THE UPPER TROUGH AMPLIFIES NORTH OF THE AREA...THE NEXT COLD FRONT WILL MOVE OFF THE N FLORIDA COAST TONIGHT. MODEL GUIDANCE SUGGESTS THE TROUGH MORPHING INTO A WEAK SURFACE LOW ALONG THE FRONTAL BOUNDARY AND LIFTING OUT TOWARD BERMUDA...BUT MODELS DIFFER ON THE TIMING...WITH THE CONSENSUS MOVING THE LOW NORTHWARD TO BERMUDA LATE FRI NIGHT. THE TRAILING TROUGH WILL EXTEND FROM THE LOW PRES NEAR BERMUDA TO THE SOUTHERN BAHAMAS BY FRI NIGHT...AND FROM 31N60W TO NEAR THE MONA PASSAGE BY SUN. THE DEVELOPMENT OF THE LOW ALONG THE FRONT WILL TIGHTEN THE PRES GRADIENT BETWEEN THE LOW AND HIGH PRES BUILDING BEHIND THE FRONT OVER THE EASTERN U.S. THIS IN TURN WILL RESULT IN A BROAD AREA OF STRONG NE WINDS...PERHAPS AS HIGH AS 30 KT... BEHIND THE FRONT BY LATE SAT. ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER AGUIRRE. TROPICAL PREDICTION CENTER.