000 AGXX40 KNHC 040725 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 325 AM EDT Wed Oct 4 2017 Marine Weather Discussion for the Gulf of Mexico, Caribbean Sea, and Tropical North Atlantic from 07N to 19N between 55W and 64W and the Southwest North Atlantic including the Bahamas. ...GULF OF MEXICO... A tight gradient remains in place between strong high pressure stretched out across the U.S. Mid-Atlantic states and troughing over the northern Caribbean and southern Gulf. Recent scatterometer passes indicated a broad swath of near gale to gale force NE to E winds across the E central Gulf, and a gale warning has been issued through at least early this morning, mainly for frequent gusts. A surface trough continues to remain stationary from NW to SE across the Veracruz offshore waters, with fresh to strong NW winds W of the trough. Fresh to strong winds prevail elsewhere across the basin, except moderate to fresh in the SW Gulf. Seas are mainly 8 to 13 ft, highest where the gale force winds are, except 5 to 8 ft in the SW Gulf. The strong winds will persist through late week as low pressure now over the far SW Caribbean moves northward and approaches the southern Gulf. While there is a general consensus among various global models regarding the movement of this low into the Gulf, there remains some difference on exact placement and timing of the approaching low. The official forecast follows closer to the ECMWF showing the low pressure reaching the vicinity of the NE tip of the Yucatan Peninsula or Yucatan Channel Fri evening, then accelerating as it moves NW or N through the central Gulf, possibly as a tropical cyclone. The latest GFS track is more to the W compared to the ECMWF, and the latest GFS is more conservative with regard to the strength of the ECMWF, which is a flip-flop from earlier runs. Conditions should become much more tranquil by early next week as Atlantic ridging NE of the area builds in the wake of any low, with moderate return flow dominating the basin. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... An area of low pressure continues to become more organized over the far SW Caribbean. A recent scatterometer showed a closed low along the monsoon trough near 11.5N81W, with some convective banding features already present. A tropical wave reaching from the low to western Cuba is slowly moving across the western Caribbean toward Central America. An upper trough is expected to dig across Florida into the Yucatan peninsula through the next couple of days, providing exhaust to the thunderstorms brewing near the low pressure and allowing it to deepen as it moves northward to the NW Caribbean or Gulf of Honduras through Thu. The low should approach the vicinity of the NE tip of the Yucatan Peninsula or Yucatan Channel by Fri evening, moving N of the area into the southern Gulf of Mexico thereafter. Strong southerly winds and building seas will follow along with the low pressure area. This low has the possibility of becoming a tropical cyclone. Elsewhere, moderate trades and 3 to 5 ft seas prevail. Moderate winds will become mainly SE to S across the basin as the low progresses northward in the western Caribbean through early Fri, then will back to the E for the end of the week into the weekend. A tropical wave in the eastern Caribbean will eventually become absorbed into the broad low circulation in the western Caribbean. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The remnants of a front, now having more of the appearance of a shear line, persist from 26N65W to the central Bahamas. High pressure continues to build down from the N and support strong near gale force NE to E flow to the N of this boundary, with mainly moderate to fresh easterly flow S of the boundary, except now fresh to strong W of 70W based on a recent scatterometer pass. This pass also showed near gale to gale force winds N of the boundary between 70W and 80W where a gale warning remains in effect until around 12 UTC. These stronger winds will gradually diminish to fresh to strong gradient flow later today. Seas are 8 to 14 ft N of the boundary, and 4 to 7 ft S of the boundary. Broad surface troughing extends from the western Bahamas to western Cuba moving W toward the Straits of Florida with numerous showers and scattered thunderstorms. The trough will continue to shift W through the Straits of Florida for the remainder of today and tonight, with weak low pressure possible developing along it. The pressure gradient will weaken significantly across the basin in the wake of the trough. The weak ridging looks to then hold in place for the upcoming weekend, with much more tranquil marine conditions possible. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... .GMZ013...N CENTRAL GULF INCLUDING FLOWER GARDEN BANKS MARINE SANCTUARY... Gale Warning early today. .GMZ015...NE GULF N OF 25N E OF 87W... Gale Warning early today. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W... Gale Warning early today. .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... Gale Warning early today. .AMZ117...BAHAMAS INCLUDING CAY SAL BANK... Gale Warning early today. .AMZ119...ATLANTIC FROM 22N TO 27N E OF BAHAMAS TO 70W... Gale Warning early today. $$ *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.nhc.noaa.gov/marine $$ .Forecaster Lewitsky. National Hurricane Center.