000 AGXX40 KNHC 230546 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 146 AM EDT MON MAR 23 2015 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 BLENDED WITH PREVIOUS OFFICIAL FORECAST THROUGH WED NIGHT WITH THE 12Z ECMWF ADDED THU ONWARD. A BLEND OF THE TAFB NWPS WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS THROUGH WED NIGHT WITH THE EC WAVE ADDED THU ONWARD. MEDIUM CONFIDENCE. WINDS AND SEAS ARE FORECAST TO REMAIN BELOW THE ADVISORY CONDITIONS OF 20-25 KT AND 8 FT...RESPECTIVELY...UNTIL AFTER A COLD FRONT MOVES INTO THE NW GULF LATE THU. THE 00Z GFS AND UKMET AND THE 12Z ECMWF AGREE THAT WINDS WILL BUILD BEHIND THE FRONT AFTER IT HAS MOVED INTO THE NW GULF AS SHORTWAVE ENERGY ALOFT THAT FIRST PASSES THROUGH THE SOUTHWESTERN U.S. MAKES ITS WAY INTO THE LEADING EDGE OF THE DEEP LAYERED TROUGH. THE 00Z GFS IS STRONGER AND FASTER WITH THIS ENERGY THAN THE UKMET AND ECMWF AND BUILDS STRONGER WIND BEHIND THE FRONT THU NIGHT...BUT ALL OF THE MODELS AGREE ON WINDS INCREASING TO AT LEAST A FRESH BREEZE BEHIND THE FRONT BY 06Z FRI. AT THIS POINT...THE 00Z GFS CARRIED NEAR GALE FORCE WINDS ALONG THE COAST OF VERACRUZ WHILE THE UKMET AND ECMWF DO NOT CARRY WINDS OVER 20 KT. THE 00Z GEFS HAS A 20 PERCENT CHANCE OF GALE WINDS AT 06Z FRI AND AS HIGH AS A 30 PERCENT CHANCE AT 12Z. HOWEVER...SINCE THERE IS LITTLE SUPPORT AMONG THE OTHER GLOBAL MODELS AND NON-GFS-BASED ENSEMBLES FOR WINDS AS STRONG AS THOSE SEEN IN THE GFS...A BLEND OF THE ECMWF AND GFS SEEMS BEST BY THU. FOR WAVES...THE TAFB NWPS SEEMED REASONABLE THROUGH WED NIGHT WITH THE EC WAVE ADDED TO THE MIX THU THROUGH THE END OF THE PERIOD FRI NIGHT WHEN THE ECMWF WAS ADDED TO THE WIND FORECAST. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. TAFB NWPS USED FOR WAVE PARAMETERS IN THE CARIBBEAN WITH THE 12Z EC WAVE BLENDED WITH THE PREVIOUS OFFICIAL FORECAST IN THE TROPICAL ATLC. HIGH CONFIDENCE. WEAK ATLC RIDGING N OF THE AREA COMBINED WITH LOW PRES OVER NW COLOMBIA WILL SUPPORT PULSES OF 20-25 KT NE WINDS WITHIN 90 NM OF THE COAST OF COLOMBIA EACH NIGHT THROUGH TUE NIGHT...DIMINISHING TO 15-20 KT BY LATE MORNING. ON WED NIGHT...THE MODELS AGREE ON BUILDING HIGH PRES OVER THE SW N ATLC AND ALLOW A FRESH TO STRONG BREEZE TO EXPAND OVER A LARGER AREA OFF THE COAST OF COLOMBIA AND STRETCH OVER MUCH OF THE CENTRAL CARIBBEAN THU NIGHT AND FRI NIGHT. WINDS WILL ALSO INCREASE IN THE GULF OF HONDURAS WED NIGHT AS THE SUBTROPICAL HIGH TO THE N STRENGTHENS. THESE WINDS SHOULD DIMINISH FRI NIGHT WHEN THE COLD FRONT IN THE GULF OF MEXICO DIMINISHES THE PRES GRADIENT OVER THE AREA. THE 00Z GFS WAS USED TO POPULATE THIS AREA AS IT HAS THE HIGHEST RESOLUTION AND GENERALLY DOES BEST IN THIS AREA AND IS REASONABLY CLOSE TO THE PREFERRED SOLUTION TO THE N. THE NWPS WAS PRIMARILY RELIED ON FOR SEAS IN THE CARIBBEAN...BUT IT CONTINUES TO BE 1-2 FT TOO LOW WITH SEAS IN THE TROPICAL N ATLC COMPARED TO OBSERVATIONS. THE EC WAVE WAS BLENDED WITH THE PREVIOUS FORECAST TO ADJUST FOR THE LOW VALUES SEEN IN THE NWPS COMPARED TO BUOY OBSERVATIONS AND ALTIMETER PASSES INITIALLY. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: THE 00Z GFS AND 12Z ECMWF BLENDED WITH THE PREVIOUS OFFICIAL FORECAST. A BLEND OF MWW3 AND EC WAVE WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. THE 00Z GFS AND 12Z ECMWF DIVERGE WITH THE STRENGTH OF THE WINDS BEHIND THE WAVY FRONT OVER N WATERS BY MON NIGHT. THE ECMWF CARRIES NEAR GALE FORCE WINDS HERE WHILE THE GFS SHOWS A FRESH BREEZE. THE UKMET SIDES WITH THE STRONGER ECMWF WHILE THE GEFS DOES NOT SHOW A CHANCE OF WINDS ABOVE ADVISORY CRITERIA HERE. THE ECMWF HAS BEEN CONSISTENT WITH THIS STRONG SOLUTION. A BLEND OF THE GFS AND ECMWF SHOULD KEEP WINDS AT ADVISORY CRITERIA MON NIGHT. THERE IS BETTER AGREEMENT AMONG THE GUIDANCE ON 20-25 KT E-SE WINDS OFF THE NE FL COAST TUE NIGHT AND WED AS HIGH PRES BUILDS OVER BEHIND THE FRONT AND SLIDES E. BY FRI MORNING...THE GFS AND UKMET CARRY THE NEXT FRONT OFF THE GEORGIA COAST WHILE THE ECMWF IS ABOUT 6 HOURS SLOWER. THE GEFS MEAN AND EC ENS MEAN SUGGEST A SOLUTION THAT IS A BLEND OF THE GFS AND ECMWF. OVERALL...A BLEND OF THE GFS AND ECMWF SEEMS BEST. THE 12Z EC WAVE AND LATEST MWW3 WERE USED TO ADJUST THE SEAS. THE EC WAVE CONTINUES TO PERFORM BETTER COMPARED TO OBSERVATIONS WITH THE NORTHERLY SWELL OVER THE ATLC VERSUS THE MWW3. THE NWPS HAD SOME PROBLEMS WITH INFLATED VALUES SE OF THE BAHAMAS THAT MADE IT LOOK UNREALISTIC IN THE REGION WHERE IT GENERALLY ADDS THE MOST VALUE...SO THE MWW3 WAS BLENDED WITH THE EC WAVE TO ACCOUNT FOR THE PREFERENCE TOWARD THE GFS/ECMWF FOR THE WINDS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.