000 AGXX40 KNHC 090707 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 307 AM EDT SAT APR 9 2016 MARINE WEATHER DISCUSSION FOR THE GULF OF MEXICO...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W...AND THE SW N ATLANTIC INCLUDING THE BAHAMAS. ...GULF OF MEXICO... MODEL PREFERENCE: 00Z GFS FORECAST BLENDED WITH THE OFFICIAL WIND FORECAST THROUGH MON NIGHT THEN 12Z/08 ECMWF ADDED. THE 00Z NWPS BLENDED WITH THE OFFICIAL WAVE FORECAST. MEDIUM CONFIDENCE. THE 00Z GFS FORECAST IS STRONGER THAN THE OTHER MODELS WITH THE WINDS BUILDING BEHIND THE FRONT IN THE SE GULF SUN MORNING AS WELL AS ALONG THE NW COASTS OF CUBA AND THE YUCATAN PENINSULA SUN NIGHT AND MON NIGHT. THE STRONGER GFS SEEMS REASONABLE NEAR THE TERRAIN AS IT GENERALLY HANDLES THESE SITUATIONS BETTER THAN THE WEAKER MODELS. GIVEN THE STRENGTH OF THE COLD AIR WHICH IS EXPECTED BY THE LOCAL FORECAST OFFICES TO KNOCK TEMPERATURES DOWN AROUND 7-10 DEGREES BELOW NORMAL...THE GFS APPEARS REASONABLE WITH THE WINDS BEHIND THE COLD FRONT AS WELL. LARGER DIFFERENCES COME INTO PLAY BY 12Z TUE WHEN THE 12Z/08 ECMWF CARRIES A COLD FRONT INTO THE NW GULF. THE 00Z GFS AND UKMET WAIT TO MOVE THE FRONT INTO THE N GULF UNTIL 06Z WED. BY LATE WED...THE ECMWF BEGINS TO DEVELOP A SURFACE LOW ALONG THE FRONT OVER THE NW GULF AND INCREASES WINDS TO AS HIGH AS 30 KT NEAR SHORE. THE GFS AND UKMET SHOW INVERTED TROUGHING HERE...BUT ARE MUCH WEAKER WITH THE WIND FIELD. THE EC ENS MEAN SIDES WITH THE FRONTAL TIMING OF THE ECMWF. THE GEFS LIES BETWEEN THE GFS AND ECMWF TIMING. THE LOCAL FORECAST OFFICES FAVORED STRONGER WINDS NEAR THE FRONT THAN THE GFS...BUT NOT AS STRONG AS THE ECMWF. GIVEN THIS...USED A BLEND OF THESE MODELS TO ADJUST THE WIND GRIDS. THE NWPS SEEMS REASONABLE FOR ADJUSTING THE WAVE HEIGHTS. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS FORECAST BLENDED WITH THE OFFICIAL WIND FORECAST. THE 00Z NWPS BLENDED WITH THE OFFICIAL WAVE FORECAST IN THE CARIBBEAN WITH 12Z/08 EC WAVE BLENDED WITH OFFICIAL IN THE TROPICAL N ATLC. MEDIUM CONFIDENCE. THE GALE WARNING FOR WATERS WITHIN 90 NM OF THE COAST OF COLOMBIA WILL BE PUSHED UP TO BEGIN IMMEDIATELY WHEN THE 06Z TEXT PRODUCT PACKAGE IS RELEASED. THE WIND GRIDS HAVE ALREADY BEEN ADJUSTED TO SHOW GALES IN THE LATE NIGHT TO EARLY MORNING HOURS TODAY THROUGH EARLY MON. THIS IS IN LINE WITH THE 00Z GFS FORECAST WHICH IS STRONGER THAN THE 00Z UKMET AND 12Z/07 ECMWF...BUT NEARLY ALWAYS HAS A BETTER HANDLE ON THE TERRAIN IMPACTS IN THIS REGION. THIS IS THE ONLY AREA WHERE SEAS ARE EXPECTED TO EXCEED 8 FT DURING THE FORECAST PERIOD. THE 00Z NWPS WAS USED TO ADJUST SEAS. A WEAKENING COLD FRONT SHOULD BRING A SURGE OF FRESH NE WINDS TO THE YUCATAN CHANNEL AND THE LEE OF CUBA SAT NIGHT AND EARLY SUN AS WELL AS IN THE WINDWARD PASSAGE AND ALONG THE S CENTRAL COAST OF THE DOMINICAN REPUBLIC SUN NIGHT...BUT NONE OF THE MODELS ALLOW WINDS TO REACH A STRONG BREEZE. THE SAME IS TRUE OF A REINFORCING FRONT EXPECTED TO BRING A FRESH NE BREEZE TO THE LEE OF CUBA EARLY MON MORNING. AGAIN...THE 00Z NWPS SEEMED REASONABLE FOR ADJUSTING SEAS IN THE CARIBBEAN. IT IS A DIFFERENT STORY WITH THE SWELL IN THE TROPICAL ATLC WHERE A 2236Z ALTIMETER PASS SHOWED SEAS TO 8.5 FT JUST E OF THE EASTERN LEEWARD ISLANDS. THE MWW3 IS 2 FT TOO LOW HERE AND THE NWPS AND 00Z UKMET ARE ABOUT A FOOT TOO LOW WHILE THE EC WAVE IS AROUND A HALF FOOT TOO LOW. THE EC WAVE GENERALLY HANDLES THE LONG-PERIOD SWELL BETTER IN THE OPEN ATLC THAN THE OTHER MODELS...SO IT WAS RELIED ON HERE FOR SEAS. THE GFS AND ECMWF FORECASTS ARE SIMILAR ENOUGH OVER THE ATLC THAT USING THE EC WAVE FORECAST SHOULD NOT PROVE PROBLEMATIC HERE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL BLEND BLENDED WITH THE OFFICIAL WIND FORECAST. THE 00Z NWPS AND 12Z/08 EC WAVE BLENDED WITH THE OFFICIAL WAVE FORECAST. MEDIUM CONFIDENCE. AGAIN...THE HIGHER SEAS SEEN IN THE 12Z/08 EC WAVE ARE MATCHING UP BETTER TO THE ALTIMETER PASS EXTENDING THROUGH THE NE WATERS TO JUST E OF THE AREA S OF 27N. THE EC WAVE GENERALLY CARRIES MORE OF A SWELL COMPONENT IN THE OPEN ATLC THAT CONTINUES TO COMPARE BETTER TO OBSERVATIONS THAN THE MWW3...WITH THE NWPS LOOKING MORE LIKE A COMPROMISE BETWEEN THE TWO MODELS. THE MODELS ARE IN REASONABLE AGREEMENT WITH THE TIMING OF THE COLD FRONTS EXPECTED TO BEGIN PILING UP ACROSS WATERS FROM BERMUDA TO THE SOUTHERN BAHAMAS SUN. THE GFS IS SLIGHTLY SLOWER TO INCREASE WINDS TO A STRONG BREEZE SAT NIGHT THAN THE ECMWF AND UKMET. THE GFS CARRIES STRONGER WINDS BEHIND THE FRONT SUN AFTERNOON AS THE FRONTS MERGE. THIS IDEA HAS MORE SUPPORT FROM THE UKMET THAN THE ECMWF. TAKING A BLEND OF THESE MODELS AND BUMPING UP THE WINDS SLIGHTLY HAS HELPED IDENTIFY THE AREAS WHERE WINDS ARE MORE LIKELY TO BE A FRESH TO STRONG BREEZE...WITH THE CENTRAL BAHAMAS BEING FAVORED SUN AFTERNOON AND EVENING. CONFIDENCE LOWERS AS THE FRONT STALLS SUN NIGHT AND BEGINS TO RETROGRADE. THE GFS CARRIES LIGHTER WINDS HERE THAN THE ECMWF AND UKMET. THE ECMWF AND EC WAVE ARE MORE AGGRESSIVE WHILE THE UKMET AND UKMET WAVE LIE IN BETWEEN. CONFIDENCE IS LOW IN ANY ONE SOLUTION...SO A BLEND WAS CONTINUED THROUGH THE FORECAST PERIOD FOR WIND. A BLEND OF THE 00Z NWPS AND 12Z/07 EC WAVE WITH THE OFFICIAL WAVE FORECAST ALSO SEEMED REASONABLE. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE WARNING EARLY TODAY. GALE WARNING TONIGHT. GALE WARNING SUN NIGHT. GALE CONDITIONS POSSIBLE SUN NIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *FOR DETAILED ZONE DESCRIPTIONS PLEASE VISIT: HTTP://WWW.NHC.NOAA.GOV/ABOUTTAFBPROD.SHTML#OWF NOTE: GRIDDED MARINE FORECASTS ARE AVAILABLE IN THE NATIONAL DIGITAL FORECAST DATABASE (NDFD) AT: HTTP://WWW.NHC.NOAA.GOV/MARINE/GRIDS.PHP FOR ADDITIONAL INFORMATION PLEASE VISIT: HTTP://WWW.HURRICANE WARNINGS.GOV/MARINE $$ .FORECASTER SCHAUER. NATIONAL HURRICANE CENTER.