000 AGXX40 KNHC 110649 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 250 AM EDT WED MAY 11 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. SW N ATLC AND TROPICAL ATLC... TROUGHING JUST W OF THE AZORES HAS FINALLY SHIFTED EASTWARD ALLOWING THE SUBTROPICAL RIDGE TO ESTABLISH ITSELF OVER FORECAST WATERS E OF 50W AND PROVIDING FRESH TRADES OVER FAR SOUTHERN HIGH SEAS WATERS ACCORDING TO THE 0020 UTC ASCAT PASS. OVER THE SW N ATLC...A DEEP LAYERED LOW CENTERED JUST N OF THE AREA HAS SENT A COLD FRONT SOUTHWARD THROUGH MUCH OF THE AREA E OF THE BAHAMAS AND NOW LIES FROM 31N53W TO 25N60W TO 23N75W. THE 0026 UTC ASCAT PASS SHOWS WINDS E OF THE FRONT ARE CURRENTLY AROUND 20 KT BUT WILL DIMINISH TODAY AS THE FRONT WEAKENS AND LOWER PRES AMPLIFIED TO ITS W. THE PRIMARY SURFACE LOW ASSOCIATED WITH THE DEEP LAYERED LOW N OF THE AREA IS CURRENTLY MAKING ITS CLOSEST APPROACH TO BERMUDA AND IS SUPPLYING NORTHERLY SWELL IN THE 10-15 FT RANGE AS WELL AS WIDESPREAD FRESH TO STRONG W WINDS BEHIND THE FRONT WHICH WILL PERSIST THROUGH THE DAY TODAY BEFORE BACKING OFF TO FRESH WINDS THROUGH FRI AS THE SURFACE REFLECTION OF A SECOND VORT WRAPPING AROUND THE DEEP LAYERED LOW PASSES JUST N OF THE AREA. BY SAT...THE BROAD SURFACE LOW PRES BEGINS TO MOVE NE AND WINDS DIMINISH FURTHER. THE MODELS HAVE COME INTO MUCH BETTER AGREEMENT HERE...ESPECIALLY CONSIDERING THE COMPLICATED PATTERN WITH VORTICITY CENTERS WHICH FUJIWARA ABOUT THE UPPER LOW CENTER. THE GFS LOOKS REASONABLE WITH THIS FEATURE THROUGH THE PERIOD. BY...A NEW FRONT MOVES OFF THE SE UNITED STATES COAST. THE 00Z GFS AND UKMET ARE IN GOOD AGREEMENT WITH THE FRONTAL TIMING WHILE THE ECMWF IS SLIGHTLY SLOWER. THE MORE IMPORTANT DIFFERENCE BETWEEN THESE MODELS IS THAT THE GFS IS DEEPER WITH THE TROUGHING ASSOCIATED WITH THE FRONT AND BUILDS WINDS TO 25 KT AHEAD OF THE FRONT OVER THE SW N ATLC. THE UKMET LOOKS LIKE A COMPROMISE BETWEEN THE DEEPER GFS AND WEAKER ECMWF HERE. IT DOES NOT ALLOW WINDS TO GET TO 25 KT. USED THE UKMET FOR THE WEEKEND FORECAST IN NW WATERS. CARIBBEAN... WITH THE SUBTROPICAL RIDGE DISRUPTED BY TROUGHING JUST W OF THE AZORES AND BUILDING TROUGHING N OF THE CARIBBEAN THE LAST FEW DAYS...THE AREA OF FRESH TRADES HAS SHRUNK TO THE COAST OF COLOMBIA. THE REMNANTS OF A COLD FRONT THAT WAS ASSOCIATED WITH THIS TROUGHING NEAR THE AZORES CONTINUES TO BE A FOCUS FOR SHOWERS IN THE NE CARIBBEAN. DEEP SOUTHERLY FLOW ON THE EASTERN SIDE OF THE DEEP LAYER LOW JUST N OF THE SW N ATLC ZONE WILL TRANSPORT MOISTURE NORTHWARD ACROSS THE EASTERN CARIBBEAN AND SUPPLY MORE FUEL FOR PRECIPITATION NEAR THESE FRONTAL REMNANTS...WHICH IS EXPECTED TO MERGE WITH THE REMAINS OF THE COLD FRONT ASSOCIATED WITH THE SW N ATLC LOW...THU THROUGH SAT. PREVIOUSLY...THE MOST SIGNIFICANT DIFFERENCE BETWEEN THE GFS AND ECMWF CAME IN THE EASTERN CARIBBEAN SAT WHEN THERE WAS SOME DEBATE ABOUT BUILDING FRESH SE FLOW ON THE E SIDE OF THE LOW LEVEL TROUGH LINGERING OVER THE AREA. THE GFS HAS BACKED OFF TOWARD THE WEAKER ECMWF SOLUTION. HOWEVER..THE UKMET STILL SHOWS 20 KT WINDS. WILL SIDE WITH THE MORE RELIABLE GFS/ECMWF FOR NOW. MEANWHILE...THE PRES GRADIENT HAS INCREASED BETWEEN STATIONARY HIGH PRES OVER THE NE GULF OF MEXICO AND AMPLIFYING TROUGHING OVER THE U.S. SOUTHERN PLAINS AND NORTHERN MEXICO AND SHOULD REMAIN THIS WAY THROUGH THU. THIS WILL RESULT IN FRESH E WINDS IN THE GULF OF HONDURAS TODAY THROUGH THU. SAW NO REASON TO STRAY FAR FROM THE GFS FORECAST HERE. BUOY 42056 WAS ALREADY AT 19 KT AT 0500 UTC. GULF OF MEXICO... THE PATTERN WILL REMAIN RELATIVELY STAGNANT THROUGH THU OVER THE GULF WITH HIGH PRES OVER THE NE GULF AND LOWER PRES OVER SOUTHERN U.S. PLAINS AND NORTHERN MEXICO FORCING FRESH TO STRONG SE RETURN FLOW OVER THE WESTERN GULF. BY SAT...A FRONT IS EXPECTED TO MOVE EASTWARD INTO THE NW GULF AND THROUGH THE LOWER MISSISSIPPI VALLEY. THIS WILL WEAKEN THE HIGH PRES CENTER AND DISPLACE IT SLIGHTLY SOUTHWARD...WEAKENING THE WINDS ACROSS THE WESTERN GULF FRI. THE MODELS DIFFER WITH THE TIMING OF THE FRONT AS IT MOVES OFFSHORE...WITH THE GFS DOING SO LATE FRI NIGHT AND THE UKMET AND ECMWF WAITING UNTIL SAT MORNING. AS EXPLAINED IN THE SW N ATLC SECTION...THE UKMET IS A COMPROMISE SOLUTION WITH THE STRENGTH OF THE TROUGHING ASSOCIATED WITH THE FRONT OVER THE FORECAST AREA. THIS HOLDS TRUE OVER THE GULF AS WELL. THE UKMET WILL BE FAVORED WITH THE FORECAST OF THIS FRONT OVER THE GULF. WARNINGS.. ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER