000 AGXX40 KNHC 120749 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 349 AM EDT THU MAY 12 2016 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: 00Z GFS BLEND WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. THE LATEST SYNOPTIC ANALYSIS HAS WEAK HIGH PRES RIDGING EXTENDING FROM THE WRN ATLC WSW ACROSS THE NRN GULF TO NEAR 94W. BUOY OBSERVATIONS AND PARTIAL ASCAT DATA SHOW SE TO S MODERATE FLOW THROUGHOUT...WITH THE EXCEPTION OF THE WATERS SURROUNDING THE NRN YUCATAN PENINSULA AND N TO 22.5N BETWEEN 88W-90W WHERE A TIGHT GRADIENT IS SUPPORTING NE-E WINDS OF 20-25 KT. THESE WINDS ARE FORECAST TO DIMINISH TO 15-20 KT LATER THIS MORNING. THE BUOYS ALONG WITH RECENT ALTIMETER PASSES SHOW SEAS IN THE RANGE OF 3-6 FT...EXCEPT FOR LOWER SEAS OF 1-2 FT N OF A LINE FROM NE TX TO 28N88W TO THE GULF SIDE OF THE LOWER FL KEYS. HIGHER SEAS OF 3-5 FT ARE IN THE STRAITS OF FL UNDER E-SE 15-20 KT WINDS. THESE WINDS ARE FORECAST TO DIMINISH TO 10-15 KT TONIGHT...AND TO NE-E 5-10 KT FRI WITH THE 3-5 FT SEAS SLOWLY SUBSIDING TO 2-3 FT BY FRI. LITTLE IN THE WAY OF CHANGES ARE IN STORE FOR THE AREA FOR THE DURATION OF THIS FORECAST PERIOD. THE WEAK HIGH PRES RIDGE IS FORECAST BY THE MODELS TO SHIFT E OF AREA TONIGHT IN RESPONSE TO A WEAK COLD FRONT THAT APPROACHES THE NW WATERS. THE COLD FRONT WILL QUICKLY SWEEP ACROSS THE NORTHERN FRI AND FRI NIGHT FOLLOWED BY WEAK HIGH PRES THAT SETTLES IN OVER THE CENTRAL PORTION BY SAT NIGHT WITH GENTLE ANTICYCLONIC FLOW ACROSS THE ERN GULF PORTION...AND GENTLE TO MODERATE FLOW OVER THE ERN HALF OF THE CENTRAL GULF PORTION. THE HIGH WILL THEN SHIFT TO THE ERN GULF BY MON WITH SE MODERATE RETURN FLOW SETTING UP OVER MUCH OF THE WESTERN WATERS. AS DURATION INCREASES WITH THESE WINDS ...SEAS WILL BUILD TO AROUND 7 FT IN THE NW GULF LATE SUN ...AND CONTINUE INTO LATE MON. A DIURNAL TROUGH WILL CONTINUE TO FORM OVER THE YUCATAN PENINSULA DURING THE EVENINGS...AND SHIFT WESTWARD ACROSS THE SW GULF IN THE OVERNIGHT AND MORNING HOURS WHILE WEAKENING. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 00Z GFS BLEND WITH PREVIOUS FORECAST FOR WINDS. FOR WAVEHEIGHTS USED A BLEND OF 00Z MWW3 WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. WATER VAPOR SHOWS A PERSISTENT UPPER TROUGH OVER THE CENTRAL CARIBBEAN WITH AXIS STRETCHING FROM THE SE BAHAMAS TO THE WINDWARD PASSAGE... AND TO 16N74W...TO 13N77W AND TO CENTRAL PANAMA. THE TROUGH HAS WEAKENED SOME SINCE YESTERDAY. ASSOCIATED SHOWERS AND TSTMS TO ITS E HAVE DIMINISHED IN COVERAGE. SCATTERED SHOWERS AND ISOLATED TSTMS ARE MAINLY CONFINED TO THE FAR ERN CARIBBEAN SEA E OF ABOUT 74W. THE TROUGH IS FORECAST TO CONTINUE TO WEAKEN AS IT MOVES SLOWLY EASTWARD THROUGH FRI. LATEST AND CURRENT BUOY OBSERVATIONS INDICATE GENTLE TO MODERATE TRADES THROUGHOUT THE CARIBBEAN...EXCEPT FOR THE AREA IN THE NW CARIBBEAN S OF 17N BETWEEN 85W-87W...AND GULF OF HONDURAS WHERE 0326Z ASCAT PASS INDICATED E WINDS OF 20-25 KT. THESE WINDS ARE FORECAST TO DIMINISH TO 15-20 BY 12Z THIS MORNING. MODERATE NE-E TRADES ARE ACROSS THE TROPICAL N ATLC. THE OBSERVATIONS REVEAL SEAS IN THE 5-6 FT RANGE E OF 81W...EXCEPT FOR A POCKET OF 6-8 FT SEAS IN THE CENTRAL CARIBBEAN FROM 11N-13N BETWEEN 73W-77W...AND LOWER SEAS OF 3-5 FT W OF 81W. LOWER SEAS OF 1-3 FT ARE IN THE WRN CARIBBEAN SEA WITHIN 60 NM S OF CUBA...AND ALSO SW OF A LINE FROM SRN BELIZE TO 15N82W TO 09N80W. SEAS HAVE LOWERED TO 5-6 FT IN THE TROPICAL N ATLC. WEAK HIGH PRES WILL REMAIN N OF THE AREA THROUGH FRI WITH THE RESULTANT PRES GRADIENT SUPPORTING MAINLY MODERATE TRADES THROUGHOUT. FRESH NE-E WINDS ARE FORECAST TO EXPAND IN COVERAGE IN THE S AND S CENTRAL CARIBBEAN (ZONES AMZ031 AND AMZ0330 BEGINNING FRI EVENING...AND THROUGH MON AS STRONG CENTRAL ATLC HIGH PRES RIDGING BEGINS TO BUILD SW INDUCING A TIGHTER GRADIENT OVER MUCH OF THE CENTRAL CARIBBEAN. SEAS OF 8 FT IN THOSE ZONES ARE FORECAST BY THE WAVEWATCH GUIDANCE TO BUILD TO 11-12 FT MON WITH THE 8 FT SEA LINE EXPANDING N TO NEAR 15N...E TO 70W AND W TO 78W AT THAT TIME. SEAS ELSEWHERE ARE EXPECTED TO REMAIN BELOW 8 FT ELSWHERE THROUGH THE FORECAST PERIOD. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 00Z GFS BLENDED WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS USED BLEND OF 00Z MWW3 WITH PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. THE PRELIMINARY 06Z SURFACE ANALYSIS HAS A WEAK SURFACE TROUGH EXTENDING ALONG A PSN FROM NEAR 29N72W TO THE SE BAHAMAS AS DEPICTED ON THE 0148Z ASCAT PASS. ANOTHER WEAK TROUGH IS OVER THE SE PORTION S OF 22N NEAR 68W. A 1022 MB HIGH CENTER IS JUST N OF THE AREA NEAR 32N73W WITH A RIDGE EXTENDING WSW TO ACROSS NRN FL. CURRENT BUOY ALONG WITH THE 0206 ASCAT PASS DEPICT MODERATE NE-E WINDS S OF 25N W OF THE TROUGH...AND GENTLE SE-S WINDS NE-E WINDS N OF 25N W OF THE TROUGH EXCEPT FOR MODERATE SE-S WINDS OVER THE FAR NW WATERS. GENTLE TO MODERATE E WINDS ARE TO THE E OF THE TROUGH...EXCEPT FOR SE-S WINDS N OF 27N. OBSERVED SEA STATE IS THAT OF SEAS IN THE RANGE OF 4-6 FT E OF THE BAHAMAS...EXCEPT FOR A POCKET OF 5-7 FT S OF 23N E OF 66W. W AND SW OF THE BAHAMAS SEAS ARE IN THE 1-2 FT RANGE...EXCEPT FOR HIGHER SEAS OF 4-6 FT IN THE STRAITS OF FL. SEAS OF 2-4 FT ARE N OF THE BAHAMAS W OF 77W. THE 4-6 FT SEAS IN THE STRAITS OF FL ARE FORECAST TO LOWER TO 3-4 FT TONIGHT AND TO 2-3 FT FRI. THE FORECAST WILL HAVE LITTLE IN THE WAY OF CHANGES FROM PREVIOUS ONES AS WIND/WAVE MODEL GUIDANCE USED IN THE NDFD GRIDS CONTINUES TO RELATIVELY MATCH WELL WITH BUOY...SHIP AND ALTIMETER REPORTS. THE ONLY EXCEPTION IS IN THE STRAITS OF FL WHERE SEAS AGAIN THERE WERE ADJUSTED UPWARD 2 FT MORE THAN THE DETERMINISTIC GFS MWW3 OUTPUT USING GUIDANCE FROM THE NWPS TAFB WAVE OUTPUT. THE WEAK TROUGHS WILL CONTINUE TO MOVE WESTWARD...AND PASS ACROSS THE BAHAMAS THROUGH FRI. AN INCREASE OF LOW LEVEL MOISTURE RELATED TO THE FIRST TROUGH IS FORECAST TO REACH THE WATERS BETWEEN THE BAHAMAS AND S FL ON FRI AS A WEAK COLD FRONT APPROACHES THE SE U.S. BY LATE FRI. THE FRONT WILL ENTER THE FAR NW WATERS LATE FRI NIGHT...AND CONTINUE TO WEAKEN OVER THE N CENTRAL WATERS SAT. THE SRN PORTION OF THE FRONT WILL EXTEND SW TO CENTRAL FL MOST PROBABLY AS A TROUGH INTO SAT NIGHT. ANOTHER WEAK COLD FRONT WILL MOVE OFF THE U.S SE COAST SAT NIGHT... AND QUICKLY MOVE ACROSS THE NW AND N CENTRAL WATERS THROUGH SUN NIGHT. SW WINDS AHEAD OF BOTH FRONTS WILL BE IN THE MODERATE CATEGORY. GENTLE N-NE WINDS WILL FOLLOW THE FRONTS UNDER A WEAK PRES PATTERN AS WEAK HIGH PRES SETTLES IN OVER THE BASIN N AND NE OF THE BAHAMAS. SEAS ARE FORECAST TO BE LOW...IN THE RANGE OF ABOUT 2-4 FT WITH THE THE WEAK FRONTS. THE HIGHEST SEAS WILL BE FOUND OVER THE SE PORTION OF THE BASIN WHERE A LONG ELY FETCH THERE FROM THE CENTRAL ATLC IS EXPECTED TO KEEP SEAS IN THE 5-6 FT RANGE THROUGH SUN NIGHT...THEN LOWERING SLIGHTLY MON. SCATTERED SHOWER AND TSTM ACTIVITY IS EXPECTED ALONG AND AHEAD OF THE FRONT....SOME OF WHICH MAY CONTAIN STRONG GUSTY WINDS AND FREQUENT LIGHTNING STRIKES. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS II COLLABORATION CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 AGUIRRE. NATIONAL HURRICANE CENTER.