000 AGXX40 KNHC 121643 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 1243 PM EDT Wed Jul 12 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... An E to W ridge will meander from the Fl Big Bend to the NE Tx coast through Thu. The ridge will then shift NW on Fri, re- orientating from N to S across the western gulf waters on Sat. The northern extension of a tropical wave currently over the NW Caribbean, and a broad inverted trough currently passing W through the Bahamas, will merge on Thu night resulting in a broad inverted trough over the SE gulf beginning on Fri morning. This merged trough will shift NW, and extend NE from 22N94W to the Fl Big Bend on Sat, then continue NW and extend across the N- central and NE waters on Sun with light to gentle winds throughout the gulf. An inverted thermal trough will develop over the Yucatan Peninsula during the late afternoons into the early evening hours, and move W-NW during the overnight hours, and dissipate over the SW Gulf by late each morning. Expect a moderate to fresh NE-E-SE wind shift, and seas to 5 ft, along the trough through Thu night, then a gentle to moderate wind shift is forecast along the trough through Sat night, becoming a moderate shift again on Sun night. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A tropical wave currently along 82W will continue W at 18 kt passing through the NW Caribbean tonight and Thu accompanied by a brief NE-E moderate-fresh wind shift. Atlc high pressure is weakening resulting in diminishing trades across the S-central Caribbean. Expect strong nocturnal NE trades only within 60 nm of the NW coast of Colombia, and across the Gulf of Venezuela through Sun night. A second tropical wave is passing through the Lesser Antilles at 15 kt accompanied by scattered showers, and will reach the central Caribbean on Thu night and Fri. ..SW N ATLANTIC INCLUDING THE BAHAMAS... A broad low level trough currently between 75W-79W will continue to shift W through Thu accompanied by SCT RW/ISOL TS. A second trough is analyzed to the S of 26N along 72W, and is also accompanied by SCT RW/ISOL TS which extends SE to over the Virgin Islands. This system will continue W into the upcoming weekend spreading the convection across the Bahamas and Old Bahama Channel, and later across the Bahama Channel. An E to W ridge extending from Bermuda to extreme NE Fl will shift N of the area as the troughs continue westward, then rebuild and meander from Bermuda to Port Canaveral on Sat and Sun. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... None. $$ *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.