000 AGXX40 KNHC 100711 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 310 AM EDT THU MAY 10 2012 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND SOUTHWEST NORTH ATLC S OF 31N W OF 55W. GULF OF MEXICO... THE MODELS ARE COMING INTO BETTER AGREEMENT ON THE SYSTEM MOVING INTO THE GULF OF MEXICO ON FRI. THE 00Z GFS NO LONGER GENERATES GALE FORCE WINDS IN THE NW GULF. IT NOW KEEPS WINDS TO 25 KT OR LESS LIKE THE 00Z UKMET AND ECMWF. THE ECMWF IS STRONGER ON FRI...GETTING WINDS UP TO 25 KT IN THE NW GULF ON FRI AHEAD OF THE MAIN LOW CENTER. THE GFS AND UKMET CONTINUE TO CARRY THE LOW PRES SYSTEM TO THE TX COAST SAT MORNING AND EASTWARD ALONG THE COAST UNTIL IT TRACKS NE INTO THE LOWER MISSISSIPPI VALLEY SUN. MEANWHILE...THE 00Z ECMWF TRACKS THE SURFACE LOW CONSIDERABLY FARTHER W AND INLAND. WITH THE CMC FAVORING THE GFS/UKMET LOW TRACK...THE ECMWF SEEMS TO BE AN OUTLIER. THE GFS HAS TRENDED TOWARD THE UKMET...SO THE GRIDS WILL BE ADJUSTED TOWARD THE MORE CONSISTENT UKMET SOLUTION. CARIBBEAN SEA AND TROPICAL N ATLC... A WEAK TROUGH WILL MIGRATE INTO THE CENTRAL CARIBBEAN THROUGH FRI WHEN IT WILL BEGIN TO LIFT NORTHWARD IN ADVANCE OF A COLD FRONT OVER THE SW N ATLC. AT THE SAME TIME...RIDGING WILL BUILD OVER THE CENTRAL ATLC AND WINDS ARE EXPECTED TO INCREASE TO 20 KT OVER THE TROPICAL N ATLC AND E CARIBBEAN AS THE PRES GRADIENT TIGHTENS BETWEEN THESE FEATURES BEGINNING THIS EVENING. THE UKMET HAS COME INTO BETTER AGREEMENT WITH THE GFS AND ECMWF ON THIS SCENARIO. LARGER MODEL DIFFERENCES CAN BE FOUND IN THE SIGNIFICANT WAVE HEIGHT FORECASTS...WITH THE GFS-BASED WW3 SHOWING 8 FT IN THE E CARIB AND TROPICAL N ATLC BY 18Z FRI WHILE THE UKMET-WAVE GETS SEAS TO 8 FT IN THE TROPICAL N ATLC BY 12Z FRI AND IN THE CENTRAL CARIB 18Z SAT AND THE ECMWF-WAVE SEES 8 FT IN THE TROPICAL N ATLC 06Z SAT AND IN THE CENTRAL CARIB 12Z SUN. WITH A SHORTER FETCH IN THE EASTERN CARIBBEAN UNDER EASTERLY FLOW...WOULD THINK THE GFS MAY BE TOO FAST TO CHURN UP THE SEAS. THE UKMET SEEMS TO BE A COMPROMISE SOLUTION. IN THE GULF OF HONDURAS...THE PRES GRADIENT WILL BE TIGHT ENOUGH OVER THE WEEKEND TO SUPPORT SOLID 20 KT WINDS 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 STRONGER WINDS OF THE 00Z ECMWF AND UKMET COMPARE BETTER TO 0412 UTC OSCAT AND THE 0256 UTC ASCAT PASSES OVER WATERS N OF 30N AHEAD OF THE COLD FRONT FROM 31N78W TO 29N81W. THE GFS ONLY BRINGS WINDS TO 20 KT RATHER THAN 25 KT LIKE THESE MODELS. BY 18Z SUN...THE GFS DEVELOPS A LOW PRES SYSTEM N OF THE AREA NEAR 39N54W ALONG THIS WEAKENING FRONT. IT IS STRONGER WITH THIS FRONTAL WAVE THAN THE OTHER MODELS AND DRAGS THE REMAINS OF THE FRONT EASTWARD AWAY FROM THE AREA MORE QUICKLY. THE UKMET IS A BIT STRONGER WITH THE WINDS NE OF THE BAHAMAS AT THIS TIME THAN THE ECMWF...BUT THE MODELS GENERALLY AGREE ON THE POSITION OF THE FRONTAL REMAINS. A BLEND OF THE UKMET AND ECMWF SEEMS REASONABLE HERE THROUGH SAT. ON SUN...THE SYSTEM IN THE GULF BEGINS TO LIFT NORTHWARD INTO THE LOWER MISSISSIPPI VALLEY...LOWERING PRESSURES OVER THE EASTERN PORTION OF THE SW N ATLC ZONE AND STEERING THE FRONTAL REMAINS NORTHWESTWARD. THE ECMWF IS NOT FAVORED WITH ITS MORE NORTHWARD SOLUTION WITH THE GULF SYSTEM. THE GRIDS WERE ADJUSTED TOWARD THE UKMET SUN AND MON. 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 GULF OF MEXICO... .NONE. CARIBBEAN SEA... .NONE. ATLANTIC... .NONE. FOR ADDITIONAL INFORMATION PLEASE VISIT WWW.HURRICANES.GOV/MARINE $$ FORECASTER SCHAUER