000 AGXX40 KNHC 080703 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 305 AM EDT TUE MAY 08 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... A COLD FRONT IS EXPECTED TO REACH THE N GULF COASTAL PLAIN OVERNIGHT WED NIGHT. THE 00Z GFS AND UKMET ARE FASTER TO CARRY THE FRONT EASTWARD THAN THE 00Z GFS AND THEY INCREASE WINDS TO 20 KT BEHIND THE FRONT IN THE NW GULF. A BLEND OF THE GFS/UKMET AND ECMWF SEEMS REASONABLE TO USE TO ADJUST THE GRIDS. THIS WILL KEEP WINDS BELOW 20 KT IN THE OFFSHORE WATERS. BY THU...TROUGHING BEGINS TO BUILD IN THE SW GULF AHEAD OF AN UPPER LOW OVER THE TX BIG BEND. THE GFS CONTINUES TO HAVE THE MOST EXPANSIVE AREA OF 20 KT WINDS WHILE THE ECMWF HAS BACKED OFF ON THE EXTENT OF ITS 20 KT WIND FIELD. THE UKMET LOOKS LIKE A GOOD COMPROMISE IN THE SW GULF ON THU. ON FRI...THE GFS BECOMES A SIGNIFICANT OUTLIER BY INTENSIFYING A MID LEVEL VORTICITY CENTER ON THE LEADING EDGE OF THE LOW OVER THE NW GULF. THE SURFACE REFLECTION OF THIS SYSTEM GENERATES GALE FORCE WINDS. THE OTHER MODELS DO NOT SUPPORT THIS SCENARIO. THE UKMET AND ECMWF CARRY A SLOW MOVING INVERTED TROUGH INTO THE W GULF FRI AND SAT. THE ECMWF DOES NOT GENERATE 25 KT WINDS WITH THE SYSTEM DESPITE THE BUILDING RIDGING OVER THE E GULF FRI AND SAT THAT SHOULD INCREASE THE PRES GRADIENT. AGAIN...THE UKMET SEEMS TO BE A COMPROMISE SOLUTION AND WILL BE USED TO ADJUST THE GRIDS FRI AND SAT. CARIBBEAN SEA AND TROPICAL N ATLC... A TROUGH CONTINUES TO LINGER OVER THE EASTERN CARIBBEAN. WINDS ARE LIGHT AROUND THE TROUGH...BUT IT IS A FOCUS FOR PRECIPITATION. THE TROUGH WILL MIGRATE W OVER THE NEXT FEW DAYS. RIDGING WILL BUILD OVER THE CENTRAL ATLC BY THU. WINDS ARE EXPECTED TO INCREASE TO 20 KT OVER THE TROPICAL N ATLC AND E CARIBBEAN AS THE PRES GRADIENT TIGHTENS BETWEEN THESE FEATURES. THE ECMWF AND GFS ARE IN REASONABLY GOOD AGREEMENT ON THIS SCENARIO WHILE THE UKMET BUILDS THE PRES GRADIENT FARTHER NE OVER THE TROPICAL N ATLC. A BLEND OF THE GFS AND ECMWF WILL BE USED TO ADJUST THE GRIDS HERE THU THROUGH SAT. IN THE GULF OF HONDURAS...THE PRES GRADIENT WILL INCREASE THU AND FRI AS TROUGHING BUILDS OVER THE WESTERN GULF OF MEXICO. THE UKMET IS FAVORED WITH THE FORECAST IN THE GULF AT THIS POINT IN THE PERIOD...SO ITS SOLUTION WAS USED TO ADJUST THE GRIDS HERE AS WELL. SW N ATLANTIC... THE MODELS HAVE COME INTO REASONABLE AGREEMENT ON THE EVOLUTION OF THE LOW PRES SYSTEM AND ITS ASSOCIATED FRONT FOUND N OF THE BAHAMAS INTO N FL THAT WILL RETROGRADING NORTHWARD AHEAD OF THE COLD FRONT MENTIONED IN THE GULF OF MEXICO SECTION. SHIP H3VU SHOWS 25 KT WINDS AND 9 FT SEAS NEAR 30N73W AT 06Z. THE ECMWF IS THE STRONGEST SOLUTION HERE AND MOST CLOSELY MATCHES THIS OBSERVATION. THE FORECAST WILL BE ADJUSTED TOWARD ITS SOLUTION TODAY AND TOWARD A BLEND OF THE GFS AND ECMWF BY TONIGHT AS THE COLD FRONT MENTIONED IN THE GULF OF MEXICO SECTION MOVES INTO THE ATLC. THE GFS CONTINUES TO BE SLOWER THAN THE ECMWF WITH THIS COLD FRONT FRI AND SAT...WITH THE GFS BUILDING STRONGER WINDS BEHIND THE FRONT. LIKE IN THE GULF...THE UKMET FAVORS THE GFS HERE. 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