000 AGXX40 KNHC 070702 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 305 AM EDT MON MAY 07 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THERE ARE NO SIGNIFICANT SENSIBLE WX DIFFERENCE AMONG THE MODELS UNTIL A COLD FRONT REACHES THE N GULF COASTAL PLAIN OVERNIGHT WED NIGHT. THE TREND IN THE 00Z GFS AND UKMET IS TOWARD A WEAKER FRONT COMPARED TO THE MAY 06/00Z RUNS. THE UKMET STILL BRIEFLY HANGS ON TO A SMALL POCKET OF 20 KT WINDS IN THE COASTAL WATERS OFF THE TX/LA BORDER THU MORNING...BUT THE GFS AND ECMWF DO NOT. THE WEAKER GFS/ECMWF SOLUTIONS FIT THE TREND AND WILL BE USED TO ADJUST THE GRIDS. BY THU...THE 00Z GFS...UKMET...AND ECMWF ALL AGREE ON ALLOWING TROUGHING TO LINGER OVER THE BAY OF CAMPECHE AND FORCE 20 KT WINDS IN THE SW GULF BETWEEN IT AND HIGH PRES BEHIND THE COLD FRONT. THE GFS HAS THE MOST EXPANSIVE AREA OF 20 KT WINDS. THE GRIDS WILL BE HEDGED TOWARD THE ECMWF HERE. LARGER MODEL DIFFERENCES COME INTO PLAY IN THE W GULF ON FRI. THE 00Z GFS CARRIES AN INTENSE MID LEVEL VORTICITY CENTER FROM TX INTO THE GULF LATE FRI. THE SURFACE REFLECTION OF THIS SYSTEM IS ALSO INTENSE...GENERATING GALE FORCE WINDS IN THE NW GULF. THE ECMWF ALSO CARRIES A SMALL...STRONG LOW OFF THE TX COAST FRI WITH 25 KT WINDS ASSOCIATED WITH IT BEFORE IT DIMINISHES AT THE END OF THE PERIOD FRI NIGHT. THE UKMET BARELY BRINGS WINDS TO 20 KT HERE. AFRAID TO GO AGAINST BOTH THE GFS AND ECMWF HERE...SO WILL HEDGE TOWARD THE WEAKER ECMWF. CARIBBEAN SEA... TROUGHING OVER THE CENTRAL ATLC HAS WEAKENED THE SUBTROPICAL RIDGING OVER THE CARIBBEAN AND LESSENED THE PRES GRADIENT YIELDING A GENTLE TO MODERATE BREEZE AND SEAS 5 FT OR LESS. THESE CONDITIONS ARE EXPECTED TO CONTINUE THROUGH WED. THE 0214 UTC ASCAT PASS AND LOCAL OBSERVATIONS SHOW WINDS ARE GENERALLY 5-10 KT ON EITHER SIDE OF THE TROUGH THAT EXTENDS FROM THE VIRGIN ISLANDS TO 12N70W...AND THERE IS NO HINT AT A LOW PRES SYSTEM DEVELOPING ALONG THE TROUGH LIKE RUNS FROM THE GFS SEVERAL DAYS AGO HAD SUGGESTED WOULD BE BEGINNING AROUND NOW. THE 00Z GFS HAS TRENDED WEAKER AND NOW ALLOWS THIS TROUGH TO REMAIN IN THE E CARIBBEAN...WITH 20 KT WINDS DEVELOPING OVER THE TROPICAL N ATLC THU INTO FRI AS RIDGING BUILDS TO THE N. THE GFS IS IN BETTER AGREEMENT WITH THE ECMWF HERE THAN IT HAS BEEN IN SEVERAL DAYS. AS MENTIONED IN THE GULF OF MEXICO SECTION...THERE IS AGREEMENT AMONG THE MODELS ON THE PRESENCE OF AN INVERTED TROUGH IN THE BAY OF CAMPECHE THU AND FRI. THE COMBINATION OF THIS TROUGHING AND RIDGING BUILDING WESTWARD THROUGH THE STRAITS OF FLORIDA SHOULD GENERATE 20 KT WINDS IN THE GULF OF HONDURAS IN THE MORNING HRS ACCORDING TO THE GFS...UKMET...AND ECMWF SOLUTIONS. ATLANTIC... PLEASE SEE THE DISCUSSION IN THE CARIBBEAN SECTION ABOVE ABOUT THE TROUGHING IN THE EASTERN CARIBBEAN THAT IS EXPECTED TO FORCE 20 KT WINDS IN THE TROPICAL N ATLC THU INTO FRI AS RIDGING TO THE N EXPANDS. FARTHER N...THE MODELS HAVE COME INTO BETTER AGREEMENT ON THE LOW PRES SYSTEM AND ITS ASSOCIATED FRONT FOUND N OF THE BAHAMAS INTO N FL THAT WILL STALL TONIGHT BEFORE RETROGRADING NORTHWARD AHEAD OF THE COLD FRONT MENTIONED IN THE GULF OF MEXICO SECTION. THE GFS AND UKMET FAVOR WINDS TO 25 KT WITH THIS LOW TODAY WHICH SEEMS REASONABLE GIVEN THE CURRENT CONDITIONS CAPTURED BY THE 0218 UTC ASCAT PASS N OF THE LOW AND THE HIGH PRES BUILDING TO ITS N TODAY. THEIR SOLUTIONS ARE FAVORED OVER THE WEAKER ECMWF TODAY AND TUE. THE COLD FRONT WILL MOVE INTO NW WATERS EARLY THU...WITH THE UKMET A SLOW OUTLIER. A BLEND OF THE GFS AND ECMWF LOOKS MOST REASONABLE HERE AND WILL BE USED TO ADJUST THE GRIDS WED THROUGH FRI. NOTE... EFFECTIVE APR 3, 2012 AT 1800 UTC THE OFFSHORE WATERS FORECAST ZONES CHANGED FOR THE CARIBBEAN AND SW N ATLANTIC AND THE GULF OF MEXICO. ISSUANCE TIME FOR THE GULF OF MEXICO OFFSHORE WATERS FORECASTS IS REFERENCED TO THE EASTERN TIME ZONE. FOR DETAILS SEE WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF GRIDDED MARINE OUTPUT IS AVAILABLE AT WWW.NHC.NOAA.GOV/TAFB/GRIDDED_MARINE (LOWER CASE). GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER