000 AGXX40 KNHC 071833 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 233 PM EDT TUE APR 7 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: 12 UTC GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. USED NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. THE MAIN FEATURE IS HIGH PRES THAT EXTENDS FROM THE WESTERN ATLC SW ACROSS THE FAR NORTHERN PORTION OF THE GULF AND TO NE TEXAS. THE ASSOCIATED GRADIENT CONTINUES TO SUPPORT MODERATE TO LOCALLY FRESH E-SE RETURN FLOW ACROSS THE GULF WITH BUOYS REPORTING SEAS IN THE 2-4 FT RANGE WITH THE EXCEPTIONS BEING IN THE EASTERN PART OF ZONE 025 WHERE THE GRADIENT BETWEEN THE CLIMATOLOGICAL TROUGH ALONG 93W AND THE RIDGE TO ITS N SUPPORTS PULSING NE-E 20-25 KT WINDS THERE...BUT ARE MAINLY CONFINED TO ALONG AND WITHIN 60 NM OF THE COAST. THE OTHER EXCEPTION IS WITH SEAS OVER THE FAR NE GULF WHERE SEA HEIGHTS ARE LOWER IN THE 1-2 FT RANGE. THE AREAS OF DENSE FOG REPORTED EARLIER THIS MORNING IN THE NW GULF HAVE FOR THE MOST PART DISPERSED WITH JUST A FEW SPOTS ALONG AND NEAR THE TEXAS COAST REPORTING REDUCED VISIBILITIES. MODEL GUIDANCE INDICATES MINOR CHANGES EXPECTED OVERALL WITH RESPECT TO ONGOING WINDS AND SEAS AS HIGH PRES REMAINS THE PRIMARY FEATURE IN CONTROL OF THE GULF'S WEATHER AND EXISTING GRADIENT. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 12 UTC GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. USED A BLEND OF THE 12 UTC MWW3 WITH NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. MOSTLY MODERATE NE-E TRADE WINDS ARE PRESENT OVER THE AREA WITH THE EXCEPTION OF THE S CENTRAL CARIBBEAN AND WATERS ALONG CENTRAL HISPANIOLA...AND WITHIN 60 NM OF THAT COAST WHERE FRESH NE-E WINDS ARE NOTED PER THE LATEST HIGH RESOLUTION ASCAT PASS. ANOTHER AREA OF EXCEPTION IS S OF 13N BETWEEN 74W AND 77W WHERE THE ASCAT PASS NOTED A SWATH OF STRONGER NE WINDS OF 30 KT. THESE WINDS WERE RECENTLY IN THE MINIMAL GALE FORCE RANGE DUE TO A TIGHT PRES GRADIENT FROM HIGH PRES N OF THE AREA...AND THE LOW PRES OVER NW COLOMBIA. THE BUOYS AND LATEST ALTIMETER REPORTS SHOW SEAS IN THE RANGE OF 5-7 FT...EXCEPT FOR LOWER SEAS OF 3-5 FT W OF ABOUT 80W...AND THE HIGHER SEAS OF 8-12 FT ATTRIBUTED TO THE NE 30 KT WIND AREA. THE NE 30 KT WINDS ARE FORECAST TO PULSE ONCE AGAIN TO MINIMAL GALE FORCE TONIGHT FROM 11N TO 12N BETWEEN 74W AND 77W WITH SEAS IN THE 10-14 FT RANGE...THEN DIMINISH BACK TO 30 KT EARLY WED...AND PULSE AGAIN TO 30 KT LATE THU AND FRI NIGHTS. NE-E WINDS WILL PULSE TO FRESH TO STRONG LEVELS THROUGH THE WINDWARD PASSAGE AND S OF HISPANIOLA DURING THE NEXT FEW NIGHTS AND EARLY MORNING HOURS. IN THE TROPICAL N ATLC...MODERATE TO FRESH NE-E TRADE WINDS AND 5-7 FT SEAS IN NE SWELL PREVAIL AND WILL PERSIST THROUGH THE NEXT SEVERAL DAYS. THIS IS REFLECTED IN THE NDFD WAVEHEIGHT GRIDS. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: LOW RATIO OF 12 UTC GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST. THE 12 UTC ECMWF GUIDANCE WASN'T AVAILABLE AT THE TIME THE GFE GRIDS WERE POPULATED. USED A BLEND OF THE 12 UTC MWW3 WITH NWPS FOR WAVE PARAMETERS. HIGH CONFIDENCE. THE 18 UTC PRELIMINARY ANALYSIS HAS A PRETTY WELL PRONOUNCED SURFACE TROUGH ALONG A POSITION FROM 29N65W TO 22N68W. LATEST SATELLITE IMAGERY SHOWS SCATTERED SHOWERS AND TSTMS E OF THE TROUGH AXIS TO 64W AND FROM 24.5N TO 26N. THE TROUGH APPEARS TO BE MOVING A BIT FASTER TODAY SOMEWHAT CLOSER TO THE 12 UTC ECMWF POSITION. THE TROUGH WILL BE FORECAST TO TRACK WESTWARD REACHING NEAR 70W BY LATE TONIGHT...AND BEGIN TO WEAKEN AS REACHES NEAR 72W WED AFTERNOON ...AND TO THE BAHAMAS WED NIGHT AS IT BECOMES DIFFUSE. OTHERWISE... A RIDGE PRESENTLY N OF THE FORECAST WATERS CONTROLS THE WEATHER PATTERN ACROSS THE BASIN...AND WILL CONTINUE TO DO SO THROUGHOUT THE FORECAST PERIOD. THE RIDGE IS FORECAST TO SLIDE SOUTHWARD TO ALONG WED THROUGH FRI...AND ALONG 30N FRI NIGHT INTO SAT...TO NEAR 29N LATE SAT. THE RIDGE IS FORECAST TO WEAKEN SAT NIGHT AND SUN AS A WEAK COLD FRONT SLIDES S OVER THE NW WATERS AND BECOMES STATIONARY. HIGHEST SEAS BY SUN SHOULD BE IN THE RANGE OF 5-6 FT OVER THE SE WATERS. NE-E WINDS OF 20 KT WILL PULSE ALONG THE COAST OF HISPANIOLA TO THE APPROACH OF THE WINDWARD PASSAGE. SEAS ELSEWHERE ARE EXPECTED TO BE IN THE 3-5 FT RANGE AFTER SUBSIDING FROM 5-7 FT WED AFTERNOON. THE EXCEPTION WILL BE THE WATERS WITHIN AND W OF THE BAHAMAS WHERE SEAS WILL BE LOWER...IN THE 1-3 FT RANGE. SEAS WILL BE HIGHER IN THE STRAITS OF FLORIDA...4-5 FT RANGE THROUGH FRI. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 74W AND 77W INCLUDING COLOMBIA BASIN...GALE WARNING TONIGHT. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 AGUIRRE. NATIONAL HURRICANE CENTER.