000 AGXX40 KNHC 260603 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 203 AM EDT SUN APR 26 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: 12Z ECMWF BLENDED WITH PREVIOUS OFFICIAL. TAFB NWPS BLENDED WITH PREVIOUS OFFICIAL SEAS. MEDIUM CONFIDENCE. THE 00Z GFS HAS TRENDED TOWARD THE MORE CONSISTENT ECMWF SOLUTION WITH THE COLD FRONT EXPECTED TO MOVE THROUGH THE GULF TUE AND WED. THE GFS HAS SPED UP CONSIDERABLY OVER THE LAST 24 HOURS. ITS 00Z RUN IS NOW FASTER THAN THE 12Z ECMWF. HOWEVER...SOME OF THIS SPEED IS LIKELY DUE TO GRID-SCALE FEEDBACK WHICH IS LOWERING HEIGHTS AHEAD OF THE TROUGH ALOFT...ALLOWING THE SYSTEM TO SHIFT EASTWARD WITH LESS RIDGE TO BATTLE AHEAD OF IT. THE FORECAST FOR TUE AFTERNOON LOOKS PARTICULARLY RIDDLED WITH FEEDBACK AS THE GFS DEVELOPS A SPURIOUS LOW OVER THE NE GULF WITH GALE FORCE WINDS AROUND IT. THE GEFS SHOWS NO CHANCE OF GALES HERE. THE ECMWF CONTINUES TO BE PREFERRED WITH THIS SYSTEM. THE TAFB NWPS IS BASED PRIMARILY IN ECMWF WINDS...SO IT WAS USED TO ADJUST THE SEAS. NESDIS/SAB SMOKE PRODUCTS INDICATE FIRES MAINLY FROM AGRICULTURAL BURNING CONTINUE TO SUPPLYING SMOKE AND HAZE TO A LARGE PORTION OVER THE GULF...WITH THE HIGHEST CONCENTRATION OF SMOKE FOUND S OF 24N W OF 93W. THERE ARE SCATTERED OBSERVATIONS...PRIMARILY IN THE NW GULF...OF VISIBILITIES IN THE 3-5 SM RANGE. A SURFACE TROUGH WILL MOVE W OFF THE YUCATAN PENINSULA EACH NIGHT THROUGH MON NIGHT AND MOVE W ACROSS THE SW GULF DURING THE EARLY MORNING HOURS...AND DISSIPATE BY MIDDAY. THIS WILL HELP KEEP THE HIGHEST CONCENTRATION OF SMOKE IN THE SW GULF. WINDS SHIFT NORTHERLY BEHIND THE FRONT TUE NIGHT INTO WED. THIS WILL CLEAR OUT THE WESTERN GULF...WITH SMOKE LIKELY TO TRACK EASTWARD AHEAD OF THE FRONT BEFORE IT MOVES SE OF THE GULF WED NIGHT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 12Z ECMWF BLENDED WITH PREVIOUS OFFICIAL. TAFB NWPS FOR SEAS. MEDIUM CONFIDENCE. A FRESH TO STRONG SE BREEZE IS EXPECTED TO PULSE EACH OVERNIGHT THROUGH TUE MORNING IN THE GULF OF HONDURAS ON THE S SIDE OF A DEEP LAYERED RIDGE. THE 0328Z ASCAT PASS CAPTURED THESE CONDITIONS. ASCAT ALSO SHOWED THE WINDS ALONG THE COAST OF COLOMBIA HAVE DIMINISHED PRIMARILY TO A FRESH BREEZE. AS LOW PRES BUILDS OVER THE SW N ATLC...THE SUBTROPICAL HIGH WILL SHIFT EASTWARD AND THE PRES GRADIENT WILL WEAKEN IN THE SW CARIB. LOOK FOR THE GRADIENT TO BUILD OVER THE S CENTRAL AND SE CARIB MON THROUGH THU BETWEEN THE SUBTROPICAL RIDGE AND LOWER PRES IN THE WESTERN CARIB ASSOCIATED WITH THE COLD FRONT PASSING FROM THE GULF OF MEXICO THROUGH THE YUCATAN CHANNEL OVERNIGHT WED NIGHT. A GROWING AREA OF FRESH TO STRONG TRADES IS EXPECTED MON NIGHT THROUGH THU NIGHT PRIMARILY OFF THE N CENTRAL AND NW COAST OF VENEZUELA. WITH THE ECMWF PREFERRED WITH THE PATTERN TO THE N INCLUDING THE COLD FRONT...IT SEEMS REASONABLE TO GO WITH ITS FORECAST HERE AS WELL. THIS LENDED ITSELF FOR USING THE NWPS PRIMARILY FOR THE ADJUSTMENT OF THE WAVES SINCE IT WAS BASED PRIMARILY ON EC WINDS. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 12Z ECMWF BLENDED WITH PREVIOUS OFFICIAL. EC WAVE AND TAFB NWPS FOR SEAS. MEDIUM CONFIDENCE. THE AREA OF 20-25 KT WINDS OBSERVED BY THE 0244Z ASCAT-B PASS SUGGESTS BOTH THE 00Z GFS AND 12Z ECMWF ARE UNDERDOING THE WIND FIELD OFF THE NE FLORIDA COAST THIS MORNING. BOTH MODELS SHOW WINDS INCREASING FURTHER THIS AFTERNOON IN THE NE PORTION...WITH THE GFS CALLING FOR A GALE AND THE ECMWF WAITING TILL EVENING TO POST A GALE JUST E OF ZONE AMZ115. THE 00Z GEFS SHOWS NO CHANCE OF GALES WHILE THE LATEST SREF SHOWS UP TO A 25 PERCENT CHANCE HERE. GIVEN THE WEAK INITIALIZATIONS AND THE TREND IN THE ECMWF TOWARD A STRONGER SOLUTION...WILL ADJUST THE WINDS HERE TO REFLECT GALE CONDITIONS EXPECTED IN FAR NE WATERS LATE TODAY. ELSEWHERE...CONFIDENCE HAS IMPROVED SLIGHTLY IN ABIDING BY THE MORE CONSISTENT ECMWF FORECAST WHICH CARRIES A LOW PRES SYSTEM THROUGH FAR NW WATERS LATE WED AND DEEPENS IT JUST N OF THE AREA. THE GFS HAS MADE A CHANGE TOWARD THIS SOLUTION. HOWEVER...CONFIDENCE IS LOW IN THE DETAILS OF THE GFS FORECAST AS IT APPEARS TO HAVE SOME GRID- SCALE FEEDBACK ISSUES WHICH IMPACT ITS MASS FIELDS. SEE THE GULF OF MEXICO SECTION FOR DETAILS ABOUT FEEDBACK SEEN IN THE NE GULF. THIS FEEDBACK LIKELY DRAGS THE MEAN TROUGH SEEN IN THE GFS EASTWARD ACROSS THE FLORIDA PENINSULA ON A MORE SOUTHEASTERLY PATH. THE ECMWF WAS USED TO ADJUST THE FORECAST. ITS WAVE MODEL WAS USED AS WELL...WITH CONFIDENCE HIGHER IN ITS HANDLING OF SWELL ORIGINATING N OF THE AREA THAN THE MWW3. THE TAFB NWPS WAS USED PRIMARILY AROUND THE BAHAMAS WHERE BATHYMETRY PLAYS A LARGER ROLE IN THE FORECAST FOR SEAS. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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.