176 AGXX40 KNHC 071805 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 205 PM EDT Tue Aug 7 2018 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... High pressure of 1021 mb centered over the SE CONUS extends a ridge across the Gulf waters producing mainly gentle to moderate anticyclonic flow and seas of 2 to 4 ft. By late Thu, winds will become light and variable over the NE Gulf as a trough reaches the SE CONUS and a high pressure cell develops near 26N86W. This system is forecast to persist on Fri, likely near 26N85W. A thermal trough will develop over the Yucatan Peninsula from the early evenings to overnight hours during the next several days. A surge of fresh to occasionally strong winds will be associated with this trough. The northern extent of a tropical wave, analyzed as a surface trough, has reached the SE Gulf. Moderate SE winds are noted per scatterometer data behind the trough axis, which is forecast to move westward over the SE Gulf tonight and Wed while dissipating. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A tight pressure gradient prevails across the basin between high pressure ridging N of the area, and the Colombian/Panamanian low. Early this morning, scatterometer data measured gale force winds in the Gulf of Venezuela and near the NW coast of Colombia. Then late this morning, another ASCAT pass showed a large area of 25-35 kt winds across the south-central Caribbean. Winds will diminish below gale force this afternoon, then will return and pulse again tonight, and once more Wed night. Seas will build to up to 10 to 14 ft near and just downwind of the open waters gale area, with 7 to 10 ft seas elsewhere in the central Caribbean. The aerial extent of the fresh to strong winds will increase by early Wed morning, covering roughly the Caribbean waters S of 18N between 64W and 83W. The pressure gradient will weaken slightly by the end of the week into the weekend allowing for winds and seas to diminish and subside slightly. Also, winds will pulse to fresh in the Gulf of Honduras at night through the week, reaching fresh to strong Wed night and Thu night. Seas will build to around 7 ft. A strong tropical wave, currently located along 41W, is forecast to reach the waters E of the Lesser Antilles late Thu, and move across these islands on Fri. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A ridge dominates the forecast waters anchored by a 1021 mb high pressure located near 31N70W. Under the influence of this system, light to gentle winds are noted N of 22N and E of the Bahamas, with gentle to moderate E-SE winds S of 22N and W of the Bahamas. Seas are in the 2-4 ft range E of the Bahamas, and 1-3 ft W of the Bahamas, with the exception of 4-6 ft just N of Hispaniola, where pulsing fresh to strong winds are expected during the evening and night hours. A ridge is forecast to remain in place across the forecast waters through the next several days. A surface trough is over the NE portion of the offshore forecast area (AMZ115 forecast zone) generating some convective activity. A weak low pressure is trying to form along the trough axis near 29N67W. This low is forecast by the GFS computer model to move toward the SW over the next couple of days, reaching a position near 28N64W by early Wed morning, and near 26N67W by early Thu morning. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... Gale Warning tonight into Wed night. GALE CONDITIONS POSSIBLE Sun night. .AMZ033...CARIBBEAN S OF 15N BETWEEN 64W AND 72W INCLUDING VENEZUELA BASIN... Gale Warning tonight. GALE CONDITIONS POSSIBLE Fri night. GALE CONDITIONS POSSIBLE Sat night. GALE CONDITIONS POSSIBLE Sun night. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.