000 AGXX40 KNHC 090709 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 310 AM EDT WED MAY 9 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 IN REASONABLE AGREEMENT WITH THE TRACK AND TIMING OF THE UPPER LOW MOVING THROUGH THE RIO GRANDE VALLEY INTO TX THROUGH FRI. THE 00Z GFS CONTINUES TO BE AN OUTLIER SOLUTION 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 FRI AFTERNOON THROUGH EARLY SAT MORNING AND THEN TAKES THE MAIN LOW PRES SYSTEM OFF THE TX COAST SAT MORNING AND TRACKS IT ALONG THE SOUTHERN LA COAST SUN. MEANWHILE...THE 00Z ECMWF NEVER GENERATES WINDS STRONGER THAN 20 KT AND KEEPS THE SURFACE LOW TRACK INLAND OVER THE WEEKEND. THE UKMET LOOKS LIKE A GOOD COMPROMISE WITH THE WIND SPEEDS...MAXING OUT AT 25 KT...BUT CARRIES A LOW ALONG THE GENERAL GFS TRACK. WITH BOTH THE ECMWF ENS MEAN AND THE GEFS KEEPING THE LOW TRACK ALONG THE COAST...THE ECMWF SOLUTION APPEARS TO NOT HAVE MUCH SUPPORT. THE UKMET SEEMS TO BE A COMPROMISE SOLUTION AND WILL BE USED TO ADJUST THE GRIDS FRI THROUGH SUN. CARIBBEAN SEA AND TROPICAL N ATLC... A WEAK TROUGH CONTINUES TO LINGER OVER THE EASTERN CARIBBEAN. THE TROUGH WILL MIGRATE INTO THE CENTRAL CARIBBEAN THROUGH SAT WHEN IT WILL BEGIN TO LIFT NORTHWARD IN ADVANCE OF A COLD FRONT OVER THE SW N ATLC. PRIOR TO THIS...RIDGING WILL BUILD OVER THE CENTRAL ATLC BY THU...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. 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 SUN. IN THE GULF OF HONDURAS...THE PRES GRADIENT WILL BE TIGHT ENOUGH THU NIGHT THROUGH SUN MORNING TO SUPPORT 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... NONE OF THE MODEL ARE QUITE AS EXPANSIVE WITH THE AREA OF 20 KT WINDS AROUND THE LOW PRES SYSTEM NE OF THE BAHAMAS THAN THE 00Z OBSERVATIONS OR 0138 UTC ASCAT PASS SUGGEST. THE GRIDS WILL BE ADJUSTED ACCORDINGLY. THIS LOW HAS ALREADY BEGUN TO MOVE NORTHWARD AHEAD OF THE COLD FRONT MENTIONED IN THE GULF OF MEXICO SECTION. THE GFS BUILDS SOUTHWESTERLY WINDS SE OF THE LOW CENTER TO 20 KT BY 12Z THIS MORNING. THESE STRONG WINDS S OF THE ASSOCIATED WARM FRONT SEEM UNLIKELY. THE FORECAST WILL BE ADJUSTED TOWARD THE ECMWF/UKMET THROUGH TONIGHT AS THE LOW AND THE WARM FRONT DISSIPATE AHEAD OF THE COLD FRONT. THE GFS AND ECMWF ARE IN REASONABLE AGREEMENT WITH THE FRONTAL TIMING OVER THE SW N ATLC...WITH THE UKMET AND CMC CARRYING A DEEPER INVERTED THROUGH OVER THE EASTERN PART OF THE ZONE THAN THE GFS AND ECMWF OVER THE WEEKEND. WILL STICK WITH A GFS/ECMWF BLEND HERE FOR NOW. 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