000 AGXX40 KNHC 171936 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 337 PM 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 LEVEL TROUGH HAS MOVED OFF THE MID ATLC COAST INTO THE WESTERN ATLC AND IS DRAGGING THE NORTHERN PORTION OF A FRONTAL BOUNDARY THROUGH THE EASTERN GULF WATERS. THE COLD FRONT CURRENTLY EXTENDS THROUGH FL S OF LAKE OKEECHOBEE TO FORT MYERS AND IS STATIONARY TO 26N87W AND TO 24N91W. GENERALLY MODERATE TO LIGHT WIND FLOW IS NOTED ON AREA BUOY OBSERVATIONS....WITH WINDS MORE N OF E N OF THE BOUNDARY. THE FORECAST FOR THE NEXT 24 HOURS HAS THE DEEP LAYER TROUGH DISSIPATING OVER THE EASTERN GULF. A RIDGE OF HIGH PRES WILL BUILD OVER THE EASTERN U.S. BEHIND THE FRONT. A WEAK COLD FRONT WILL DISSIPATE THU OVER THE GULF COASTAL STATES JUST AS IT REACHES THE NORTHERN GULF OF MEXICO AND A STRONGER RIDGE OF HIGH PRESSURE WILL MOVE IN BEHIND IT AND DOMINATE THE WEATHER OVER THE GULF FRI THROUGH SUN. AS THE PATTERN BECOMES MORE AMPLIFIED OVER THE WEEKEND...EXPECT EASTERLY AND SOUTHEASTERLY FLOW ON THE SOUTH EDGE OF THE RIDGE TO INCREASE OVER THE GULF. CARIBBEAN... A QUIKSCAT PASS FROM 1036 UTC 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. 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 THE DEEP LAYER TROUGH MOVING THROUGH THE WESTERN ATLC. AS THIS HIGH WEAKENS FURTHER THROUGH WED...TRADES WILL DIMINISH TO 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. OVER THE WEEKEND...EXPECT THE HIGH PRESSURE RIDGE PASSING THROUGH THE GULF OF MEXICO TO INCREASE THE PRESSURE GRADIENT OVER THE CARIBBEAN AND INCREASE WINDS ONCE AGAIN OVER 20 KT OVER MUCH OF THE WESTERN CARIBBEAN. ATLANTIC S OF 31N W OF 55W... A MID/UPPER LEVEL TROUGH HAS MOVED OFF THE MID ATLC COAST INTO THE WESTERN ATLC...WITH A DEEPENING MID LEVEL SHORTWAVE SYSTEM INDUCING A STRENGTHENING SURFACE LOW NORTH OF THE AREA WHICH WILL BE BRINGING N SWELL TO THE SW N ATLC ZONE WED THROUGH FRI. AHEAD OF THIS TROUGH...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 BUOY/SHIP OBSERVATIONS AND THE 1336 ASCAT AND 1038 QUIKSCAT PASSES. SHIP OBSERVATION ELYX3 NEAR 18N55W CONTINUED TO SHOW 9 FT SEAS EAST OF THE LESSER ANTILLES DUE TO DECAYING NE SWELL. THE COLD FRONT ASSOCIATED WITH THE LOW PRES SYSTEM NORTH OF THE AREA WAS ANALYZED FROM 31N71W TO PALM BEACH AT 1800 UTC. THE COLD FRONT WILL QUICKLY MOVE EAST OF THE AREA...BRIEFLY BUILDING WINDS TO THE 20 TO 25 KT RANGE AND USHERING IN THE NORTH SWELL. 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 THIS EVENING...WITH THE COLD FRONT TRAILING THROUGH THE CENTRAL BAHAMAS. THE HIGH PRES WEAKENS FURTHER AND SHIFTS EASTWARD. THE FRONT WILL STALL AND WEAKEN ALONG ROUGHLY 21N/22N BY LATE WED AS THE UPPER SUPPORT LIFTS OUT. 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. 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 AND LIFTING OUT TOWARD BERMUDA...BUT THEY DIFFER ON THE TIMING...WITH THE CONSENSUS MOVING THE LOW NORTHWARD OVERNIGHT 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. ATLANTIC... NONE. CARIBBEAN... NONE. GULF OF MEXICO... NONE. FORECASTER SCHAUER CLARK. TROPICAL PREDICTION CENTER.