000 AGXX40 KNHC 110717 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 317 AM EDT SAT APR 11 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: GLOBAL MODEL CONSENSUS WEAKENING FRONTAL BOUNDARY HAS DRIFTED SE ACROSS NW AND N CENTRAL PORTIONS OF GULF PST SEVERAL HOURS AND NOW SUGGESTED TO EXTEND FROM FAR W PANHANDLE OF FL ACROSS MOUTH OF MS RIVER TO JUST N OF BRO...WHERE RECENT ASCAT PASSES WERE OVER LA WATERS. MODEST RIDGE EXTENDS WWD UNDERNEATH FRONT FROM W ATLC ACROSS N CENTRAL FL TO NEAR 90W. LIGHT TO MODERATE WINDS GENERALLY PREVAIL ACROSS THE BASIN ATTM...EXCEPT 15-20 KT ALONG NW YUCATAN COAST...WHERE SEAS ARE 4-5 FT. OTHERWISE OBS SUGGEST SEAS 2-3 FT EXCEPT 1 FT BIG BEND. S/W MOVING ACROSS LOWER MS VALLEY ATTM WILL DRAG FRONT ESE ACROSS NE GULF NEXT 24 HOURS WHERE IT WILL LAY DOWN MORE E-W ALONG 29-30N AND ACROSS N FL THROUGH THIS AFTERNOON THEN BEGIN TO DRIFT NWD AND REMAIN INLAND TONIGHT AND SUN BEFORE BECOMING DIFFUSE. LITTLE CHANGE IN RECENT GUIDANCE AND THUS REASONING REMAINS UNCHANGED. WEAK RIDGING WILL REMAIN FROM BIG BEND REGION W AND SW ACROSS THE BASIN THROUGH THU TO PRODUCE MODERATE SE FLOW ACROSS MOST OF SW HALF BASIN AND LIGHT WINDS NE PART. LATE AFTERNOON-EVENING THERMAL TROUGH WILL DOMINATE WIND FLOW ACROSS N AND W COASTAL ZONES OF YUCATAN...WHERE DOWNSTREAM SEAS WILL BUILD TO 4-5 FT TODAY THEN 5-6 FT EACH EVENING BEGINNING SUN. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: LATEST GFS STRONG AND PERSISTENT UPPER RIDGE REMAINS CENTERED OVER TROPICAL N ATLC ALONG ABOUT 50W AND CONTINUES TO COMBINE WITH POCKETS OF LIGHT TO MODERATE SAL MOVING WWD ACROSS TROPICAL ATLC AND INTO E CARIB TO PRODUCE GENERALLY FAIR AND STABLE CONDITIONS ACROSS BASIN E OF 80W. ATLC RIDGE NOW CENTERED ACROSS CENTRAL ATLC EXTENDING WWD ALONG ABOUT 30N TO N FL ATTM AND COMBINING WITH MODERATELY LOW PRES ACROSS COLOMBIA TO MAINTAIN STRONG TRADES ACROSS CENTRAL PORTIONS OF BASIN. RECENT ASCAT PASSES DEPICTED 25-30 KT WINDS OFF NE COLOMBIA S OF 12.5N AND E OF 75W...AND ARE EXPECTED TO PEAK AROUND 30 KT OVERNIGHT AND NOT REACH GALES. PRES GRADIENT SUFFICIENT TO SPREAD 20 KT TRADES NWD TO JUST OFFSHORE OF S COAST OF HISPANIOLA...AND ALSO THROUGH WINDWARD PASSAGE. LITTLE CHANGE EXPECTED NEXT 24 HRS BEFORE ATLC RIDGE WEAKENS THROUGHOUT WEEK TO PRODUCE A MODEST DECREASE IN TRADES E AND CENTRAL PORTIONS. HIGH PRES TO SHIFT INTO NW ATLC BEHIND CURRENT GULFMEX COLD FRONT MON AND RIDGE SW INTO GULF...AND TIGHTEN PRES GRADIENT ENOUGH W PORTIONS TO YIELD E-SE WINDS PULSING TO 20-25 KT ACROSS GULF OF HONDURAS STARTING TONIGHT...WHERE SEAS LIKELY TO BUILD 5-7 FT EACH NIGHT. ACROSS THE TROPICAL N ATLC WATERS FRESH ENE TRADES PRESENTLY PREVAIL WITH SEAS 5-6 FT N PORTIONS AND 6-7 AND LOCALLY 8 FT S PART. EQUATORIAL ELY WAVES HAVE BEGUN TO PROPAGATE ACROSS THE ATLC ALREADY...WITH CURRENT WAVE ALONG 47W AND WILL MOVE ACROSS EXTREME S PORTIONS OF THE AREA TONIGHT THROUGH TUE. ATLC HIGH ACROSS CENTRAL ATLC WILL REMAIN DUE N OF THIS FEATURE THROUGH MON TO PRODUCE SOLID 20 KT TRADES S OF 13N OR SO THROUGH MON NIGHT WHERE SEAS WILL BUILD 7-8 FT IN TRADE WIND SWELL. THEN AS HIGH SHIFTS ENE THROUGH MID WEEK...TRADES UPSTREAM OF AREA WILL STRENGTHEN TO LONG ENE FETCH OF SOLID 20 KT AND MAINTAIN 8 FT SEAS S PORTIONS INTO MID WEEK IN WIND SWELL. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: GLOBAL MODEL CONSENSUS DAY 1-3 THEN GEFS DAY 3-7 ATLC RIDGE CONTINUES TO DOMINATES THE WATERS ANCHORED ON A 1026 MB HIGH LOCATED NEAR 29.5N51W EXTENDING WWD ALONG 30-31N TO N FL-GA COASTS. TUTT INDUCED LOW-MID LEVEL INVERTED TROFS CONTINUE TO DEVELOP S OF RIDGE AND ENTER E PORTIONS ACCOMPANIED BY MODEST MOISTURE AND SHALLOW CONVECTION. SUFFICIENT PRES GRADIENT N OF GREATER ANTILLES PRODUCE ELY TRADES 15-20 KT S OF 23N THAT WILL CONTINUE TO BE ENHANCE BY DIURNAL PROCESSES ACROSS N COASTAL ZONES OF GREATER ANTILLES EACH AFTERNOON AND EVENING...WITH MOST OBVIOUS MODEL SIGNAL ACROSS NW COAST OF HISPANIOLA AND ACROSS ENTRANCE TO WINDWARD PASSAGE. SEAS DURING EACH PULSE EXPECTED TO BUILD TO 7 FT BU AM NOT YET INCLUDING IN HSF DUE TO RETREATING HIGH. MODELS BEGIN TO DIVERGE SOMEWHAT AFTER DAY 3 AS RECENT RUNS OF ECMWF DIGGING MORE SIGNIFICANT TROFFING 45-55W...THE FAMED MID OCEANIC TROUGH...AND THIS FURTHER WEAKENS BREAK IN RIDGING THERE. 18Z MODEL ENSEMBLES WERE SIMILAR TO GFS AND UKMET RUNS AND HAVE THUS DISREGARDED ECMWF SOLUTION BEYOND DAY 3...ALTHOUGH 00Z RUN NOT YET IN. GULFMEX FRONT TO MOVE OFF SE U.S. COASTS LATER TODAY AND SINK S INTO NW PORTIONS LATE THIS EVENING AND TONIGHT...WHERE IT WILL GENERALLY LAY DOWN ALONG 29-30N AND DISSIPATE THROUGH 72HRS. NEW HIGH BUILDING OFF MID ATLC COAST BEHIND FRONT TO BRIEFLY YIELD 20-25 KT WINDS IN NARROW ZONE N OF FRONT SUN AS FRONT SINKS ALONG 30N...WITH SEAS BUILDING TO 7 FT. THIS HIGH WILL SHIFT OFF THE NE THROUGH MID WEEK WITH RIDGE EXTENDING SW TO NW BAHAMAS. COMBINATION OF NEXT FRONTAL SYSTEM APPROACHING E COAST TUE WILL YIELD MODERATE SE TO S WINDS W PORTIONS AND FL COASTAL WATERS THROUGH TUE NIGHT. MODELS DIFFERING ON LOCATION OF CYCLOGENESIS ALONG THIS FRONT TUE NIGHT-WED AND WILL WAIT FOR LATEST ECMWF FOR BETTER COMPARISON. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 STRIPLING. NATIONAL HURRICANE CENTER.