000 AGXX40 KNHC 151702 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 102 PM EDT Sat Apr 15 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 thermal trough will develop late each afternoon over the Yucatan Peninsula, and shift w across the southwestern waters, generally to s of 23N between 90W and 93W, during the overnight hours, and gradually lose identity along about 94W late each morning. Expect a ne-e-se 15-20 kt wind shift along the trough axis, with seas building to 6 ft, except fresh to strong conditions are forecast along the trough tonight and on Sun evenings with seas building briefly to 7 ft. Otherwise, a ridge extends w across the northern coastal plains with weak n to s orientated surface troughs passing w under the ridge across the n-central gulf waters accompanied by showers. Moderate to locally fresh easterlies are maintaining 3-6 ft seas. A tightening pressure gradient will increase the low level flow across the eastern gulf to a fresh to locally strong breeze through early tonight, with seas building to 8 ft in the Gulf Stream. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Strong ne nocturnal winds, and 7-9 ft seas, are expected within 150 nm of the nw coast of Colombia tonight and on Sun night. A tightening pressure gradient will support strong trades and 5-7 ft seas across the central Caribbean waters tonight then the gradient will relax. Moderate to fresh ne winds across the nw and the n-central Caribbean will increase to a fresh to locally strong breeze tonight, and again very briefly on Sun night with strongest winds to the lee of Cuba, in and downstream of the Windward Passage and to the lee the Dominican Republic. Expect seas to build to 8 ft in the longest fetch just downstream of the Windward Passage. Large n swell in the form of 7-8 ft seas will arrive at the Mona Passages late Sun night, reach the ne Caribbean Passages on Mon, and spread s across the tropical waters and Leeward passages on Mon night, and spread s across the Windwards on Tue, eventually reaching the n coast of S America on Wed. ...SW N ATLANTIC INCLUDING THE BAHAMAS... The pressure gradient between a weakening surface low pressure over the se waters a surface high over the se Conus, is supporting strong to near gale force ne flow, and 7-10 ft seas, across the waters ne of the Bahamas, and fresh to locally strong e flow across the Bahamas and Fl Straits with 4-7 ft in the open waters. The low is forecast to continue to shift se and weaken to an open trough just n of Puerto Rico this evening, then drift w and gradually dissipate just n of Hispaniola on Sun, with associated winds diminishing to less than 20 kt by late Sun night. A second low near 28N57W will shift ne of the area late this afternoon, with strong to near gale northerly flow developing across the discussion waters from 26N to 31N between 55W and 64W. Associated winds will diminish to 20 kt or less to the w of 55W on Mon morning. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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 Nelson. National Hurricane Center.