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AGXX40 KNHC 250629
MIMATS

MARINE WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
229 AM EDT SAT APR 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: 12Z ECMWF BLENDED WITH PREVIOUS OFFICIAL. TAFB NWPS BLENDED WITH PREVIOUS OFFICIAL SEAS. LOW CONFIDENCE.

S-SE FLOW DOMINATES THE GULF THIS MORNING. LOOK FOR WINDS TO BECOME MORE VARIABLE N OF 25N AS A WEAK FRONT PUSHES EASTWARD JUST N OF THE AREA TODAY. THE 00Z GFS AND 12Z ECMWF AGREE ON DIPPING A COLD FRONT INTO THE NE GULF ON MON MORNING. THE GFS KEEPS THE FRONT OVER THE NE GULF BEFORE RETREATING IT N IN ADVANCE OF THE NEXT SYSTEM WHILE THE ECMWF ALLOWS THE FRONT TO MOVE S INTO THE N CENTRAL AND NW GULF. ALOFT...THE GFS IS FASTER TO LOWER HEIGHTS HERE AND CARRIES A MORE POSITIVELY TILTED TROUGH COMING OUT OF THE ROCKIES INTO THE PLAINS ON MON COMPARED TO THE MODEL CONSENSUS. THE GFS IS FASTER TO MOVE THIS FRONT NORTHWARD OUT OF THE GULF AS A RESULT. THEN...THE GFS IS SLOWER TO CARRY THE COLD FRONT ASSOCIATED WITH THE UPPER TROUGH INTO THE NW GULF ON TUE COMPARED TO THE CONSENSUS. THE GFS CONTINUES TO BE A SLOW OUTLIER AS THE FRONT MOVES THROUGH THE GULF WED. THE ECMWF WAS PREFERRED HERE. THE TAFB NWPS WAS BASED ON ECMWF WINDS...SO ITS SOLUTION LOOKS REASONABLE HERE.

NESDIS/SAB SMOKE PRODUCTS INDICATE FIRES MAINLY FROM AGRICULTURAL BURNING ARE SUPPLYING SMOKE TO A LARGE PORTION OVER THE GULF S OF 28N WITH THE HIGHEST CONCENTRATION OF SMOKE FOUND 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 THROUGH MON 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 SHIFT NORTHERLY BEHIND THE FRONT TUE NIGHT INTO WED. THIS WILL CLEAR OUT THE WESTERN GULF...WITH SMOKE LIKELY TO TRACK EASTWARD WITH 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.

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 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. THE 0302Z ASCAT PASS SHOWS WINDS ALONG THE COAST OF COLOMBIA ARE A FRESH TO STRONG BREEZE. THESE DIURNALLY PULSING WINDS ARE EXPECTED TO DIMINISH AFTER THIS MORNING AS LOW PRES BUILDS OVER THE SW N ATLC. THIS WILL SHIFT THE SUBTROPICAL HIGH EASTWARD. THE SUBTROPICAL RIDGE WILL BUILD AGAIN TUE NIGHT THROUGH THU AS THE NEXT SYSTEM MOVES THROUGH THE GULF AND INTO THE SW N ATLC. THIS WILL SET UP THE STRONGEST GRADIENT OVER THE SE AND S CENTRAL CARIB WHERE A GROWING AREA OF FRESH TO STRONG TRADES IS EXPECTED. WITH THE ECMWF PREFERRED TO THE N...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 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 TONIGHT. THE GFS APPEARS TO HAVE SOME GRID-SCALE FEEDBACK ISSUES HERE. IT DEVELOPS A GALE OVER ZONES AMZ113 AND AMZ115 SUN. THIS IS AN OUTLIER SOLUTION. THE 12Z ECMWF CAPS WINDS AT 30 KT AS DOES THE UKMET. THE GEFS SHOWS NO CHANCE OF GALES HERE AT THAT TIME. THE ECMWF IS FAVORED HERE AS WELL AS WITH THE NEXT SYSTEM MOVING FROM THE GULF OF MEXICO INTO THE ATLC WED. SEE THE GULF OF MEXICO SECTION FOR DETAILS. 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.

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