000 AGXX40 KNHC 250633 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 233 AM EDT WED MAR 25 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. A BLEND OF THE MWW3 WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. 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 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 GFS IS DEEPER AND FASTER WITH THE DEEP LAYER TROUGH THAN THE UKMET AND 12Z ECMWF AND IS STRONGER WITH THE WINDS BEHIND THE FRONT. THE 00Z UKMET SHOWS BETTER AGREEMENT WITH THE ECMWF IN THESE REGARDS. THE GENERAL TREND IN THE MODELS OVER THE PAST FEW DAYS HAS BEEN TOWARD A STRONGER WIND SOLUTION...WITH THE GFS NOW SHOWING A 40 KT GALE ALONG THE COAST OF VERACRUZ NEAR TAMPICO THU NIGHT AND THEN IN THE FAR SW GULF FRI MORNING. THE 12Z ECMWF ALONG WITH THE 00Z UKMET AND NAM ALSO CARRY A GALE OVER THE SW GULF FRI AFTERNOON...BUT NONE ARE AS STRONG AS THE GFS NEAR TAMPICO. THE 03Z SREF PEAKS AT A 75 PERCENT CHANCE OF GALES IN THE SW GULF FRI AFTERNOON. CONFIDENCE HAS INCREASED ENOUGH TO RAISE A GALE FLAG OVER THE SW GULF FRI. THE GFS WAS THE FIRST MODEL TO CATCH ONTO THIS STRONGER TREND. CONFIDENCE IS SLIGHTLY HIGHER IN ITS SOLUTION AS A RESULT. THIS MEANT GOING WITH A FASTER SOLUTION THAN SOME OF THE OTHER MODELS. FOR WAVES...THE TAFB NWPS IS LOWER WITH THE SEAS IN THE AREA OF STRONG WINDS BEHIND THE FRONT THAN THE MWW3 BECAUSE IT RELIED ON A WEAKER WIND FORECAST THERE. THE MWW3 WAS USED TO ADJUST THE WAVE FORECAST AS A RESULT. ...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 BLENDED WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS IN THE CARIBBEAN THROUGH THU WITH MWW3 USED THU NIGHT ONWARD. THE MWW3 WAS ADDED TO THE BLEND WITH THE OFFICIAL FORECAST FOR WAVES IN THE TROPICAL N ATLC. MEDIUM CONFIDENCE. 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 AND THU NIGHT BEFORE BEGINNING TO SHRINK AGAIN FRI AS A PROGRESSIVE COLD FRONT IN THE GULF OF MEXICO SHOVES THE SUBTROPICAL HIGH E. WINDS WILL ALSO PULSE TO AT LEAST A FRESH BREEZE IN THE GULF OF HONDURAS WED NIGHT AND THU NIGHT AS THE SUBTROPICAL HIGH TO THE N STRENGTHENS. THESE WINDS SHOULD DIMINISH LATE FRI 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 THE PREFERRED SOLUTION TO THE N. THE GULF OF MEXICO COLD FRONT SHOULD PASS THROUGH THE YUCATAN CHANNEL SAT. THE MODELS DIVERGE ON THE EXACT TIMING AND STRENGTH OF THE FRONT...WITH THE 00Z GFS FASTER AND STRONGER THAN THE 00Z UKMET AND 12Z ECMWF. BLENDING THE NEW GFS INTO THE PREVIOUS FORECAST STILL CAPPED WINDS BELOW THE 20-25 KT THRESHOLD...MORE IN LINE WITH THE EURO SOLUTIONS. CONFIDENCE IS LOW ENOUGH THIS FAR OUT IN THE FORECAST TO STICK WITH THE MORE WASHED OUT SOLUTION. THE NWPS WAS PRIMARILY RELIED ON FOR SEAS THROUGH THU IN THE CARIBBEAN WITH SOME MANUAL EDITS MADE ALONG THE COAST OF COLOMBIA TOWARD SLIGHTLY HIGHER SEAS CORRESPONDING TO THE STRONGER WINDS. ONCE THE FRONT APPROACHES...WINDS FROM THE GFS...WHICH CARRIES A STRONGER FRONT MORE QUICKLY TOWARD THE CARIBBEAN...ARE FAVORED. THE MWW3 SOLUTION IS 2-3 FT HIGHER THAN THE MWW3 BEHIND THE FRONT. WHILE THE GFS WIND SOLUTION IS NOT PREFERRED VERBATIM...A STRONGER/HIGHER SOLUTION IS NEEDED TO BLEND WITH THE PREVIOUS FORECAST TO MATCH THE WIND FORECAST. THE MWW3 WAS RELIED ON FRI ONWARD TO ADJUST THE SEAS. IN THE TROPICAL N ATLC...THE TAFB NWPS STARTS OFF ABOUT 2-3 FT TOO LOW WITH SEAS OVER S WATERS WHERE NE SWELL IS A FACTOR. THE NWPS CATCHES UP TO THE SWELL IN THE MWW3 BY THU. THE MWW3 WAS USED TO ADJUST SEAS HERE. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: THE 00Z GFS BLENDED WITH THE PREVIOUS OFFICIAL FORECAST. A BLEND OF MWW3 AND TAFB NWPS WITH THE PREVIOUS FORECAST USED FOR WAVE PARAMETERS. MEDIUM CONFIDENCE. NONE OF THE MODELS ARE STRONG ENOUGH WITH THE PATCH OF 20-25 KT SE WINDS OFF THE COAST OF NE FL/SE GA ON THE E SIDE OF A SURFACE TROUGH APPROXIMATELY 70 NM OFFSHORE. THE NAM WAS THE CLOSEST SOLUTION HERE...BUT IT WAS STILL WEAK AND TOO FAR N WITH THE STRONGEST WINDS. MANUALLY ADJUSTED THIS AREA INTO THE GRIDS USING THE NAM AS A GUIDE. OTHERWISE...THE PROBLEM OF THE DAY IS THE COLD FRONT MOVING INTO THE AREA FRI AFTERNOON. THE 12Z ECMWF AND 00Z GFS ARE IN REASONABLE AGREEMENT WITH THIS TIMING WHILE THE UKMET IS SLOWER AND CARRIES STRONGER WINDS AHEAD OF THE FRONT. THE GFS/ECMWF TIMING IS PREFERRED. THE GFS IS THE MIDDLE-OF-THE-ROAD SOLUTION WITH THE STRENGTH OF THE WINDS NEAR THE BOUNDARY FRI NIGHT...WITH THE ECMWF WEAKER AND THE UKMET GENERALLY STRONGER. OVERALL...THE GFS APPEARS TO BE THE BEST SOLUTION...BUT CONFIDENCE WANES BY THE WEEKEND WHEN THE GFS BECOMES THE STRONGEST SOLUTION. FOR SEAS...THE NWPS BECOMES 2-3 FT LOWER THAN THE MWW3 FORECAST BY SAT NIGHT...REFLECTING THE WIND FORECAST FROM THE GFS. SINCE THE GFS IS FAVORED FOR ADJUSTING THE WINDS AT THAT TIME...THE MWW3 NEEDED TO BE ADDED TO THE MIX. USED BOTH THE MWW3 AND TAFB NWPS TO ADJUST THE SEAS. THIS SEEMED TO CAPTURE BOTH THE WIND FORECAST AND THE BATHYMETRIC IMPACTS NEAR THE BAHAMASREASONABLY WELL. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... .GMZ023...SW GULF S OF 22N W OF 94W... GALE CONDITIONS POSSIBLE FRI. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.