000 AGXX40 KNHC 170711 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 310 AM EDT TUE MAR 17 2009 MARINE WEATHER DISCUSSION FOR GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A MID/UPPER TROUGH FROM THE GREAT LAKES TO GEORGIA IS PUSHING EAST INTO THE WESTERN ATLC. THIS IN TURN IS INDUCING THE NORTHERN PORTION OF A FRONTAL BOUNDARY THROUGH THE NE GULF WATERS. THE COLD FRONT EXTENDS FROM CENTRAL FLORIDA JUST N OF TAMPA...TO 24N95W...THEN STATIONARY TO THE WESTERN BAY OF CAMPECHE JUST S OF VERACRUZ. GENERALLY MODERATE TO LIGHT WIND FLOW IS NOTED ON AREA BUOY OBSERVATIONS. ONE EXCEPTION IS BUOY 42039 SW OF PANAMA CITY FLORIDA...WHERE 20 TO 25 KT WERE REPORTED OVER THE LAST COUPLE OF HOURS. THIS LIKELY DUE TO NEARBY THUNDERSTORM ACTIVITY HOWEVER AND IS NOT INDICATIVE OF GRADIENT FLOW. THE FORECAST FOR THE NEXT COUPLE OF DAYS HAS THE THE UPPER TROUGH PUSHING FURTHER EAST...WITH THE COLD FRONT MOVING THROUGH SOUTH FLORIDA...AND DISSIPATING OVER THE WESTERN GULF. A RIDGE OF HIGH PRES WILL BUILD OVER THE EASTERN U.S. BEHIND THE FRONT. LIGHT TO MODERATE NE FLOW ENVELOPES THE GULF WITH SEAS LIMITED TO 5 FT OR LESS. ANOTHER LONG WAVE TROUGH DIGS THROUGH THE EASTERN U.S. THU AND FRI...PUSHING A SECOND COLD FRONT INTO THE NORTHERN GULF ON THU...WITH STRONG HIGH PRES BUILDING BEHIND THE FRONT. THE TIGHTENING PRES GRADIENT ALONG WITH WEAK COLD AIR ADVECTION WILL ALLOW FRESH NORTHERLY WINDS TO FOLLOW BEHIND THE FRONT AS IT PUSHES THROUGH THE GULF THU INTO FRI. CARIBBEAN... A QUIKSCAT PASS FROM 11Z SHOWED NE WINDS TO 30 KT OFF THE COLOMBIAN COAST...WITH A BROAD AREA OF 20 TO 25 KT WINDS OVER THE SOUTH CENTRAL CARIBBEAN BASIN. A SECOND PASS FROM 2330Z SHOWED ONLY 20 TO 25 KT ALONG THE COLOMBIAN COAST HOWEVER...ALTHOUGH THE COVERAGE OF 20 KT EASTERLY WINDS HAD SHIFTED A LITTLE FURTHER EAST. STRONG HIGH PRES NE OF THE BAHAMAS HAS BEEN THE DRIVER FOR THE ENHANCED TRADE WIND FLOW OVER THE PAST SEVERAL DAYS. THIS HIGH PRES IS STARTING TO WEAKEN AND SHIFT SE IN RESPONSE TO MID/UPPER LEVEL TROUGH AND ASSOCIATED COLD FRONT MOVING OFF THE SE U.S. COAST. AS THIS HIGH WEAKENS FURTHER THROUGH WED...TRADES WILL DIMINISH BARELY 20 KT OFF COLOMBIA AND THE EASTERN CARIBBEAN BY LATE WED. SIMILARLY LONG PERIOD SWELL THAT HAD BEEN PUSHING THROUGH THE MONA AND ANEGADA PASSAGES FOR THE PAST FEW DAYS HAS TAPERED OFF. MEANWHILE...THE FAR WESTERN PORTION OF THE COLD FRONT IS EXPECTED TO ENTER THE NW CARIBBEAN BY EARLY WED THEN STALL AND DISSIPATE INTO THU WITH LITTLE IMPACT ON WINDS OR SEAS. ATLANTIC S OF 31N W OF 55W... A WEAKENING 1024 MB HIGH PRES AREA IS CENTERED NEAR 27N64W. THIS IS MAINTAINING A BROAD SWATH OF 15 TO 20 KT TRADES MAINLY S OF 21N PER SCATTEROMETER AND BUOY OBSERVATIONS. BUOYS ALONG WITH A 2145Z JASON ALTIMETER PASS SHOW SEAS TO STILL BE 8 TO 9 FT S OF 20N EAST OF THE LESSER ANTILLES...DUE TO DECAYING NE SWELL. BUOY OBSERVATIONS OFF THE N FLORIDA COAST SHOW NW WINDS BEHIND A COLD FRONT THAT EXTENDS FROM 31N78W TO 29N81W. A 1016 MB LOW PRES AREA WAS ANALYZED ALONG THE FRONT OFF SOUTH CAROLINA. THIS FEATURE WILL DEEPEN AS IT MOVES FURTHER EAST ASSOCIATED WITH A DEEP LAYER TROUGH NOW MOVING THROUGH THE EASTERN U.S. THERE REMAIN SOME SUBTLE DIFFERENCE IN GLOBAL MODEL GUIDANCE REGARDING THE MOVEMENT AND INTENSITY OF THE THIS LOW...BUT GENERAL CONSENSUS HAS IT DEEPENING TO AROUND 1007 MB AND IN THE VICINITY OF N OF BERMUDA BY LATE TODAY...WITH THE COLD FRONT TRAILING THROUGH THE CENTRAL BAHAMAS. THE HIGH PRES WEAKENS FURTHER AND SHIFTS TO NEAR 25N55W. STRONG WINDS TO HIGH AS 25 KT CAN BE EXPECTED OVER WATERS N OF 27N TODAY INTO TONIGHT AS THE LOW MOVES ACROSS TO THE NORTH OF DISCUSSION AREA. THE FRONT WILL STALL AND WEAKEN ALONG ROUGHLY 21N/22N BY LATE WED AS THE UPPER SUPPORT LIFTS OUT. WINDS DIMINISH...BUT ANOTHER ROUND OF LONG PERIOD N TO NE SWELL UP TO AT LEAST 12 FT PUSHES SOUTH ACROSS THE REGION WED INTO THU. BY THU INTO FRI...THE NEXT MAJOR LONG WAVE TROUGH PUSHES INTO THE EASTERN U.S. WITH A STRONG SW JET ALOFT AHEAD OF THE TROUGH. DIVERGENT FLOW ALOFT ON THE RIGHT REAR OF THE JET WILL SUPPORT DEVELOPMENT OF A WEAK SURFACE TROUGH JUST EAST OF THE BAHAMAS. GLOBAL MODEL GUIDANCE IS COMING INTO BETTER AGREEMENT CONCERNING THIS FEATURE. AS THE UPPER TROUGH AMPLIFIES NORTH OF THE AREA...THE NEXT COLD FRONT MOVES OFF THE N FLORIDA COAST THU NIGHT. MODEL GUIDANCE SUGGESTS THE TROUGH MORPHING INTO A WEAK SURFACE LOW ALONG THE FRONTAL BOUNDARY FRI...AND LIFTING OUT TOWARD BERMUDA BY FRI NIGHT. THE TRAILING TROUGH EXTENDS FROM THE LOW PRES NEAR BERMUDA TO THE SOUTHERN BAHAMAS BY FRI NIGHT...AND FROM 31N60W TO NEAR THE MONA PASSAGE BY LATE SAT. THE DEVELOPMENT OF THE LOW ALONG THE FRONT WILL TIGHTEN THE PRESSURE 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.0 ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER CHRISTENSEN. TROPICAL PREDICTION CENTER.