000 AGXX40 KNHC 181858 MIMATS MARINE WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 258 PM EDT MON APR 18 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: 12Z GFS BLEND WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS USED A BLEND OF 12Z MWW3 WITH SMALL PERCENTAGE OF TAFB NWPS WAVE PARAMETERS INTO PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. A 1029 MB HIGH CENTERED OVER SOUTHWESTERN N CAROLINA EXTENDS A RIDGE S TO OVER THE EASTERN GULF THIS AFTERNOON...WHILE LOW PRES EXISTS OVER CENTRAL TEXAS AND THE GREAT PLAINS. THE RESULTING TIGHT PRES GRADIENT IS PRODUCING FRESH TO STRONG E-SE WINDS ACROSS MUCH OF THE NW AND CENTRAL WATERS. LATEST SATELLITE IMAGERY AND NWS MOSAIC DOPPLER RADAR ANIMATION REVEAL SCATTERED SHOWERS AND TSTM ACTIVITY OVER PORTIONS OF THE NW GULF AND ALONG THE TEXAS COAST SUPPORTED BY DIFFLUENT FLOW ALOFT E OF A MID TO UPPER TROUGH SITUATED OVER WESTERN TEXAS. THIS ACTIVITY IS CAPABLE OF PRODUCING STRONG GUSTY WINDS AND FREQUENT LIGHTNING STRIKES AS NOTED IN THE LIGHTNING DENSITY PRODUCT. THE ACTIVITY IS EXPECTED TO SLIDE EASTWARD OVER THE NEXT 48-72 HOURS. LATEST BUOY AND ALTIMETER PASSES SHOW SEAS IN THE RANGE OF 6-10 FT W OF A LINE FROM SE LOUISIANA TO 26N84W TO 23N84W TO THE NW YUCATAN PENINSULA. THE HIGHEST OF THESE SEAS IS CONCENTRATED NEAR 26N93W. E OF THIS SAME LINE...SEAS ARE IN THE 4-6 FT RANGE EXCEPT NE OF A LINE FROM NEAR PENSACOLA TO FLORIDA BAY WHERE SEAS THERE ARE 2-3 FT. THE OTHER EXCEPTION IS IN THE FAR SE GULF AND STRAITS OF FLORIDA WHERE SEAS ARE HIGHER...IN THE 6-8 FT RANGE. THE MAX SEAS OF 10 FT IN THE NW GULF ARE FORECAST TO SUBSIDE TO 8 FT LATER THIS AFTERNOON...AND THE 6-8 FT SEAS IN THE FAR SE GULF ARE EXPECTED TO LOWER TO 5-7 FT TONIGHT AND TO 4-6 FT LATE ON TUE. MODELS ARE IN VERY GOOD AGREEMENT THAT THE HIGH PRES RIDGE WILL CONTINUE TO BUILD S OVER THE EASTERN GULF THROUGH WED. THE RIDGE WILL WEAKEN WED NIGHT...AND BECOME RE- ESTABLISH OVER THE FAR NORTHERN GULF THU BEFORE SHIFTING E OF THE GULF ON FRI ALLOWING FOR A WEAK COLD FRONT TO MOVE ACROSS THE NW AND N PORTIONS. THE FRONT WILL MOVE ACROSS THE NE GULF FRI AFTERNOON AND EVENING... AND CONTINUE TO WEAKEN AS IT MOVES OVER THE FAR SE WATERS SAT. WEAK HIGH PRES IS FORECAST TO BUILD S OVER THE AREA BEHIND THE FRONT WITH RELATIVELY LIGHT TO GENTLE ANTICYCLONIC FLOW EXPECTED THROUGHOUT...EXCEPT IN THE EASTERN BAY OF CAMPECHE NEAR THE COAST OF THE YUCATAN PENINSULA WHERE WIND SPPEDS THERE WILL BE UNDER THE INFLUENCE OF THE YUCATAN PENINSULA TROUGH. THE FRESH TO STRONG ESE FLOW ACROSS MUCH OF THE WESTERN AND CENTRAL GULF WILL SLOWLY DIMINISH TO MODERATE TUE NIGHT THROUGH WED NIGHT AS THE PRES GRADIENT WEAKENS. A TROUGH WILL DEVELOP OVER THE YUCATAN PENINSULA EACH AFTERNOON AND WEAKEN AS IT MOVES WNW OVER WATER EACH NIGHT. THE TROUGH WILL BE FOLLOWED WITH SURGES OF FRESH TO STRONG NE TO E WINDS DURING THE OVERNIGHT HOURS THROUGH THE PERIOD. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... MODEL PREFERENCE: 12Z GFS BLEND WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS USED A BLEND OF 12Z MWW3 WITH SMALL PERCENTAGE OF TAFB NWPS WAVE PARAMETERS INTO PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE. THE CARIBBEAN BASIN IS RATHER QUIET WITH RESPECT TO FEATURES AND IMPACTS TO WINDS AND SEAS...WHICH IS PRETTY NORMAL FOR THIS TIME OF YEAR. BOTH BUOY AND ASCAT DATA CONFIRM THE QUIET CONDITIONS WITH LIGHT TO MODERATE WINDS IN THE SW CARIBBEAN NEAR THE COAST OF COLOMBIA...AND GENTLE TO MODERATE E-SE WINDS ELSEWHERE. THE ASCAT PASS FROM 1410Z SHOWED MODERATE NE WINDS THROUGH THE WINDWARD PASSAGE. SEAS ARE IN THE RANGE OF 4-6 FT IN THE S CENTRAL...AND IN PORTIONS OF THE SW CARIBBEAN AND 3-5 FT ELSEWHERE EXCEPT FOR LOWER SEAS OF 2-3 FT NEAR THE COAST OF CUBA...AND IN THE FAR EASTERN CARIBBEAN SEA. LITTLE IN THE WAY OF CHANGES ARE EXPECTED THROUGH DAY 5 WITH THE EXCEPTIONS OF TRADES PULSING TO FRESH TO STRONG EACH NIGHT S OF HISPANIOLA...AND THE APPROACH TO THE WINDWARD PASSAGE TONIGHT THROUGH FRI NIGHT. FRESH NE WINDS S OF CUBA TO 20N WILL DIMINISH TO MODERATE THIS AFTERNOON...HOWEVER FRESH TO STRONG NE WINDS ARE EXPECTED S OF EASTERN CUBA TONIGHT BEFORE DIMINISHING ON TUE. THE PRESENT WEAKENING ATLC COLD FRONT APPROACHING NW PUERTO RICO WILL MOVE INTO THE NW TROPICAL N ATLC TUE...THEN STALL AND DISSIPATE FROM NEAR 20N55W TO 18N62W BY WED NIGHT. SCATTERED SHOWERS AND TSTMS OVER MUCH OF THE NORTHERN AND CENTRAL TROPICAL N ATLC WILL PERSIST THROUGH LATE WED. SIMILAR ACTIVITY IS ALSO EXPECTED OVER MUCH OF THE EASTERN CARIBBEAN THROUGH THU AS IT LIFTS N TOWARDS PUERTO RICO AND THE ADJACENT ISLANDS BY THAT TIME. ...SW N ATLANTIC INCLUDING THE BAHAMAS... MODEL PREFERENCE: 12Z GFS BLEND WITH PREVIOUS OFFICIAL FORECAST FOR WINDS. FOR WAVEHEIGHTS USED A BLEND OF 12Z MWW3 WITH SMALL PERCENTAGE OF TAFB NWPS WAVE PARAMETERS INTO PREVIOUS OFFICIAL FORECAST. HIGH CONFIDENCE THROUGH THU NIGHT...THEN AVERAGE CONFIDENCE THEREAFTER. A WEAKENING COLD FRONT IS OVER THE FAR SE WATERS...WHILE STRONG HIGH PRES IS BUILDING S OVER THE FAR WESTERN WATERS. THE TIGHT PRES GRADIENT BETWEEN BOTH OF THESE FEATURES IS RESULTING IN MODERATE TO FRESH NW TO N WINDS OVER THE NE PORTION...AND GENTLY TO MODERATE N TO NE WINDS OVER THE WESTERN PORTION AS SEEN IN CURRENT BUOY OBSERVATIONS...AND IN RECENT SHIP AND ASCAT DATA. THE BUOY OBSERVATIONS ARE REPORTING LARGE SEAS OF 10-14 FT N OF ABOUT 26N DUE TO NE SWELL N AND NE OF THE BAHAMAS. MOSTLY GENTLE NW WINDS ARE BEHIND THE FRONT S OF 25N. SEAS ELSEWHERE ARE IN THE 6-10 FT RANGE DUE TO MIXED NE AND NW SWELL COMPONENT. A RATHER WELL DEFINED LOW PRES SYSTEM N OF THE AREA NEAR 33N62W OF 1002 MB WILL TRACK TO THE SE...AND STAY WELL TO THE NE OF THE FORECAST WATERS THROUGH WED. IT WILL PUSH A TROUGH ACROSS THE NE WATERS TONIGHT AND WED FOLLOWED BY A SURGE OF MODERATE TO FRESH NW TO N WINDS OVER THE NE WATERS ALONG WITH A NW SWELL WITH SEAS OF 9-12 FT. THE SWELL WILL DECAY TUE NIGHT AND WED WITH SEAS LOWERING TO AROUND 8 FT. THE WEAKENING COLD FRONT OVER THE FAR SE WATERS WILL MOVE ACROSS THE NW PORTION OF THE TROPICAL N ATLC WATERS TUE...THEN STALL AND DISSIPATE FROM NEAR 20N55W TO 18N62W BY WED NIGHT. HIGH PRES WILL BUILD SE ACROSS THE BASIN IN THE WAKE OF THE FRONT AND TROUGH AND WEAKEN THU NIGHT THROUGH FRI NIGHT ALLOWING FOR A WEAK COLD FRONT TO MOVE ACROSS THE NW AND N CENTRAL WATERS. THE 12 GFS INDICATES S-SW WINDS OF 10-15 KT AHEAD OF THE FRONT FRI WHILE THE 12Z ECMWF IS A LITTLE HIGHER WITH THE WINDS. FOR NOW WILL LEAN ON THE CONSERVATIVE SIDE...AND KEEP WINS OF 10-15 KT AHEAD OF THE FRONT IN THE FAR NW WATERS THU NIGHT AND FRI WITH SEAS OF 5-6 FT. $$ .WARNINGS...ANY CHANGES IMPACTING COASTAL NWS OFFICES WILL BE COORDINATED THROUGH AWIPS 12 PLANET CHAT OR BY TELEPHONE: .GULF OF MEXICO... NONE. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... NONE. .SW N ATLANTIC INCLUDING THE BAHAMAS... NONE. $$ *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 AGUIRRE. NATIONAL HURRICANE CENTER.