000 AGXX40 KNHC 270727 MIMATS MARINE WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 320 AM EDT WED MAY 27 2009 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A SHARP UPPER TROUGH IS MOVING ACROSS THE NE GULF THIS MORNING...ENHANCING A SMALL BUT VIGOROUS CLUSTER OF THUNDERSTORMS OVER THE SE GULF WATERS. OTHERWISE GENERALLY LIGHT TO MODERATE SE TO S WINDS PREVAIL AROUND A WEAK SURFACE RIDGE EXTENDING FROM THE FLORIDA BIG BEND AREA THROUGH THE TEXAS COAST. A 00Z SCATTEROMETER PASS SHOWED THE NOTABLE EXCEPTION OF 20 KT FLOW ALONG THE WEST COAST OF THE YUCATAN PENINSULA...DUE TO LOCAL DIURNAL INFLUENCES. ALTHOUGH IT IS NOT APPARENT FROM SATELLITE OR OBSERVATIONS OVERNIGHT...THERE HAVE BEEN REPORTS OF THICK SMOKE OVER THE BAY OF CAMPECHE DUE TO WILDFIRES OVER SOUTHERN MEXICO. MEANWHILE A SHORT WAVE TROUGH OVER THE CENTRAL PLAINS IS PUSHING WEAK SURFACE FRONT INTO TEXAS. THE FRONT IS EXPECTED TO MOVE INTO THE FAR NW GULF BY WED NIGHT...THEN REACH FROM THE MISSISSIPPI DELTA TO SOUTHERN TEXAS BY THU NIGHT. THE 00Z GFS RUN MAINTAINS A SMALL LOW PRES AREA FORMING ALONG THE FRONT OVER THE EASTERN GULF BY LATE THU. THE ECMWF AND UKMET SHOW ONLY MODEST TROUGHING OVER THE SW GULF THROUGH THE SAME PERIOD. THE FAIRLY STRONG SOUTHERN STREAM JET NOSING INTO THE AREA SOUTH OF THE SHORT WAVE TROUGH SHOWING UP IN ALL THE MODELS LENDS CREDENCE TO SOME SURFACE TROUGH FORMING THROUGH 48 HOURS...ALTHOUGH PERHAPS NOT STRONG AS THE GFS IS DEPICTED. WILL INTRODUCE 15 TO 20 KT FLOW INTO THE EASTERN GULF AHEAD OF THE FRONT THU...BUT OTHERWISE NO MAJOR CHANGES ANTICIPATED TO THE MARINE FORECAST. CARIBBEAN AND TROPICAL ATLC W OF 55W... A 01Z ASCAT PASS SHOWED 20 TO 25 KT TRADES PERSISTING OFF THE VENEZUELAN COAST. 20 KT WINDS WERE REPORTED AT BUOYS 42058 AND 42059 IN THE CENTRAL AND EASTERN CARIBBEAN RESPECTIVELY. THE ASCAT PASS ALSO SHOWED 20 KT TRADES N OF GUYANA AND EAST OF BARBADOS...DUE TO SURFACE HIGH PRES E OF BERMUDA. FURTHER WEST...THE ANOMALOUS WEAK PRESSURE PATTERN HAS ENDED WITH A TIGHTER PRESSURE GRADIENT BACK IN PLAY...ALLOWING 15 TO 20 KT SE FLOW TO MAKE A RESURGENCE THROUGH THE GULF OF HONDURAS. AS HIGH PRES BUILDS OVER THE WESTERN ATLC AND GULF OF MEXICO...TODAY WILL SEE AN UNBROKEN SWATH OF FRESH TRADES FROM EAST OF THE LESSER ANTILLES ACROSS THE CENTRAL CARIBBEAN TO THE BELIZE COAST...WITH PERSISTENT 20 TO 25 KT WINDS OFF WESTERN VENEZUELA AND EASTERN COLOMBIAN COASTS. THIS STRONGER FLOW IS ALLOWING SEAS TO BUILD TO 9 FT OFF VENEZUELA AND MAY REACH 10 FT BY LATE IN THE WEEK. LITTLE CHANGE IS EXPECTED IN THIS PATTERN FOR THE NEXT SEVERAL DAYS. SUBTROPICAL ATLANTIC W OF 55W... SURFACE RIDGE EXTENDS FROM JUST EAST OF BERMUDA THROUGH THE CENTRAL BAHAMAS...IN THE WAKE OF 1011 MB SURFACE LOW THAT MOVED NORTH TO OFF THE CAROLINA COAST LATE YESTERDAY. A 0140Z ASCAT PASS SHOWED 20 KT FLOW ON THE SE SIDE OF THE LOW...MAINLY N OF 28N BETWEEN 70W AND 75W...BUT OTHERWISE ASCAT AND BUOYS SHOWED GENERALLY LIGHT TO MODERATE FLOW AROUND THE RIDGE AXIS. A SMALL CLUSTER OF THUNDERSTORMS IS ONGOING NEAR THE TURKS AND CAICOS...LIKELY THE RESULT OF PRONOUNCED DIVERGENT FLOW ALOFT AT THE BASE OF A SHARPLY AMPLIFIED UPPER TROUGH. 00Z GFS INITIALIZES WITH A SURFACE TROUGH NEAR 27N70W. THERE IS SOME VAGUE EVIDENCE OF THIS FEATURE IN SATELLITE IMAGERY AND SCATTEROMETER DATA...ALTHOUGH VERY SUBTLE AND IT MAY MORE OF A MID LEVEL CIRCULATION. THE GFS CONTINUES TO DEVELOP THIS FEATURE THROUGH TODAY AS IT TRACKS NORTH...COMPLETE WITH 30 KT WINDS ON THE EASTERN SIDE OF THE LOW NEAR BERMUDA BY MIDDAY. THIS IS AGAIN SEEMS LIKE A CONVECTIVE FEEDBACK ISSUE...AND THE FORECAST WILL BE MORE CONSERVATIVE WITH GENERALLY 15 TO 20 KT. THE OTHER MATTER CONCERNS THE GFS SHOWING A CIRCULATION CROSSING SOUTH FLORIDA FROM THE GULF OF MEXICO AND MOVING NE TO THE NORTH OF THE BAHAMAS BY FRIDAY PACKING 30 KT WINDS. THIS AGAIN IS LIKELY OVERDONE. A WEAK COLD FRONT WILL MOVE INTO THE WATERS OFF N FLORIDA BY LATE FRIDAY. THE ECMWF IS A LITTLE MORE REALISTIC SHOWING ENHANCED SW FLOW AHEAD OF THE FRONT IN THE WATERS BETWEEN N FLORIDA AND BERMUDA ON SATURDAY...THEN DIMINISHING ON SUNDAY AS THE FRONT DISSIPATES. WARNINGS ATLC... .NONE. CARIBBEAN... .NONE. GULF OF MEXICO... .NONE. FORECASTER CHRISTENSEN. TROPICAL PREDICTION CENTER.