000 AGXX40 KNHC 240615 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 215 AM EDT FRI APR 24 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. 12Z EC WAVE AND 00Z TAFB NWPS BLENDED WITH PREVIOUS OFFICIAL SEAS. LOW CONFIDENCE. THE 00Z GFS AND 12Z ECMWF AGREE ON DIPPING A COLD FRONT INTO THE NE GULF ON MON MORNING AND THEN BUILD FRESH TO STRONG SOUTHERLY FLOW ACROSS THE N CENTRAL/NW GULF ON MONDAY AS THE FRONT STALLS IN THAT AREA AND BEFORE RETREATING N IN ADVANCE OF THE NEXT SYSTEM. THE ECMWF GOES ON TO SHOW STRONGER WINDS NEAR THE WARM FRONT MON NIGHT INTO TUE WHEN AN UPPER LOW BEGINS TO MOVE OUT OF THE SOUTHWEST AND THOUGH THE SOUTHERN PLAINS. THE 00Z GFS AND 12Z ECMWF DIVERGE WITH THE STRENGTH OF THE SURFACE TROUGHING EXPECTED TO MOVE E ACROSS THE GULF OF MEXICO MON NIGHT THROUGH THU NIGHT WITH THE ECMWF DEEPER THAN THE GFS WITH THE LOW PRES SYSTEM THEY BOTH TRACK THROUGH THE SOUTHERN PORTION OF THE GULF COASTAL STATES. THE 00Z UKMET SIDES WITH THE DEEPER ECMWF. THE GFS CARRIES THE ACTUAL COLD FRONT OFF THE TEXAS COAST BETWEEN 1200-1800 UTC TUE WHILE THE ECMWF IS SLIGHTLY FASTER AND ALSO HAS MORE SUPPORT FROM THE UKMET. THE GFS FOCUSES THE STRONGEST WINDS IN THE SW GULF BY WED AFTERNOON WHILE THE ECMWF SHOWS THE FRESH TO STRONG BREEZE REMAINING PRIMARILY NEAR THE LOW IN THE NORTHERN GULF. THE ECMWF PATTERN LOOKS MORE REASONABLE AND HAS MORE ENS SUPPORT. WILL SIDE WITH THE ECMWF/EC WAVE AS THE PRIMARY TOOLS FOR ADJUSTING THE FORECAST. NESDIS/SAB SMOKE PRODUCTS INDICATE FIRES MAINLY FROM AGRICULTURAL BURNING ARE SUPPLYING SMOKE TO A LARGE PORTION OVER THE GULF S OF 26N W OF 87W. THERE ARE FEW OBSERVATIONS TO CONFIRM VISIBILITIES HERE...BUT THEY ARE BELIEVED TO BE IN THE 3-5 SM RANGE IN SMOKE/HAZE. A SURFACE TROUGH WILL MOVE W OFF THE YUCATAN PENINSULA EACH NIGHT AND MOVE W ACROSS THE SW GULF DURING THE EARLY MORNING HOURS...AND DISSIPATE BY MIDDAY. THIS WILL HELP PROPEL SOME OF THE SMOKE WESTWARD TODAY. WINDS WILL PICK UP OVER THE SOUTHERN GULF OVERNIGHT FRI NIGHT AND THE MEAN FLOW MAY DIRECT SMOKE FARTHER NORTHWARD IN THE CENTRAL GULF SAT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: ECMWF BLENDED WITH PREVIOUS OFFICIAL. TAFB NWPS BLENDED WITH THE EC WAVE FOR SEAS. MEDIUM CONFIDENCE. CONFIDENCE LOWERS BY MON NIGHT WHEN THE 12Z ECMWF AND 00Z GFS BEGIN TO DIVERGE WITH THE SURFACE PATTERN N OF THE AREA. THE GFS SUPPORTS A MORE PROGRESSIVE COLD FRONT OVER THE SW N ATLC BUT IS SLOWER TO ADVANCE THE COLD FRONT THROUGH THE GULF OF MEXICO TUE INTO WED COMPARED TO THE ECMWF. THIS TIMING IS IMPORTANT IN THE AREAS WHERE THE PRESSURE GRADIENT BETWEEN RIDGING TO THE N OR NE AND CLIMATOLOGICAL LOW PRES IS DETERMINING THE STRENGTH OF THE WINDS. 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. WINDS OFF THE COAST OF COLOMBIA ARE A BIT HARDER TO PREDICT DUE TO THE VARIABILITY N OF THE AREA. THE GFS STOPS ALLOWING WINDS TO REACH THE FRESH TO STRONG BREEZE THRESHOLD CONSISTENTLY BY SAT NIGHT...THEN SHIFTS THE FRESH TO STRONG BREEZE TO THE S CENTRAL AND SE CARIB MON NIGHT. THE ECMWF IS GENERALLY WEAKER...HAVING A SMALLER AREA OF THE FRESH TO STRONG WINDS OFF COLOMBIA FRI NIGHT THAN THE GFS AND SHOWING WINDS STRENGTHENING MORE SLOWLY IN THE S CENTRAL AND SE CARIB TUE NIGHT. THE ECMWF IS PREFERRED TO THE N AND IT IS PREFERRED HERE. THERE IS SOME CONCERN THAT IS MAY BE TOO LIGHT IN THESE LOCAL AREAS...SO THE BLEND WITH THE PREVIOUS FORECAST WAS KEPT MORE HEAVILY WEIGHTED TOWARD CONTINUITY. THIS LENDED ITSELF FOR USING THE NWPS PRIMARILY FOR THE ADJUSTMENT OF THE WAVE...WITH THE EC WAVE ADDED IN TO ADJUST FOR THE PREFERRED WIND FORECAST. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: ECMWF BLENDED WITH PREVIOUS OFFICIAL. EC WAVE AND TAFB NWPS FOR SEAS. MEDIUM CONFIDENCE. THE ECMWF IS CLOSER TO THE MODEL CONSENSUS AND THE LATEST EC ENS AND GEFS MEANS WITH THE DEVELOPMENT OF THE LOW PRES SYSTEM MOVING OFF THE CAROLINA COAST SAT NIGHT. THE GFS APPEARS TO HAVE SOME GRID-SCALE FEEDBACK ISSUES HERE. IT DEVELOPS A GALE OVER ZONE AMZ113 SUN MORNING. THIS IS AN OUTLIER SOLUTION. THE ECMWF IS ALSO FAVORED WITH THE NEXT SYSTEM MOVING FROM THE GULF OF MEXICO INTO THE ATLC TUE INTO WED. 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 TAFBNWPS 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.