000 AGXX40 KNHC 201758 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 158 PM EDT Thu Jul 20 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 weak ridge will dominate the Gulf waters through Saturday producing gentle to moderate winds and seas of 1 to 3 ft, with the exception of variable winds and seas of 1-2 ft over the NE Gulf, where a weak high pressure center will prevail. On Sunday, as the ridge builds westward, expect moderate to locally fresh SE to S winds and seas of 3-5 ft across much of the west and SW Gulf through Monday night. A thermal trough will develop over the Yucatan Peninsula each evening before pushing offshore into the SW Gulf each night. The trough will drift westward during the overnight hours, and dissipate over the SW Gulf each morning. A surge of fresh to occasionally strong NE winds will accompany this trough. Seas will briefly build to 4-6 ft with these winds. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Latest scatterometer data along with ship and buoy observations, depict fresh to strong winds over the central Caribbean, moderate to fresh winds over the eastern Caribbean, and the Tropical North Atlantic forecast zones, and gentle to moderate winds over the western Caribbean. Buoy 42058 located near 15N75W is now reporting seas to 11 ft while an altimeter pass also indicated seas to 11 ft across the south-central Caribbean. The ridge north of the area will weaken this weekend. This will decrease the aerial extent of the winds with subsiding seas. The ridge will strengthen early next week which will once again increase winds and seas, particularly across the south-central Caribbean. By Monday morning, expect fresh to strong east winds across most of the waters S of 17.5N and east of 80W, with seas building again up to 11 ft across the south-central Caribbean. A very large tropical wave, with axis along 49W will move across the Tropical North Atlantic forecast zones on Friday, reaching the Lesser Antilles by Friday night into Saturday morning. A second tropical wave with axis over the Lesser Antilles will cross the eastern Caribbean through Friday, reaching the central Caribbean on Saturday, and the western Caribbean on Sunday. Pulsing fresh to locally strong winds are expected across the Windward Passage this evening, and again Friday evening. ...SW N ATLANTIC INCLUDING THE BAHAMAS... Scatterometer and surface data depict moderate to fresh winds over the southern waters, except fresh to strong winds north of Hispaniola into the Windward Passage, and gentle to moderate winds elsewhere. Seas are in the 3-4 ft range over the northern waters, 5-6 ft over the southern waters outside the Bahamas except reaching 8 ft north of Hispaniola, and 1-3 ft west of the Bahamas. A ridge, with axis along 29N/30N, will dominate the forecast region through the weekend and into early next week with little change in the marine conditions. Pulsing fresh to locally strong winds are expected just north of Hispaniola, including the approach to the Windward Passage during the evenings through the upcomimg weekend. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.nhc.noaa.gov/marine $$ .Forecaster GR. National Hurricane Center.