000 AGXX40 KNHC 011853 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 253 PM EDT Sun Oct 1 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 middle to upper level low continues to shift slowly SW across the S central Gulf, currently just off the N coast of the Yucatan, and is advecting deep layered moisture N through the Yucatan Channel and into the SE Gulf where active cnvtn persists. The low will shift further SW and across the Yucatan and into the Bay of Campeche through late Mon. A surface trough extends from 28N85W to 23N88W, where a weak early season frontal boundary has draped across the N end of this trough, where a strong pres gradient N of the boundary is producing strong NE winds around 25 kt and seas building quickly 7-10 ft. The trough will shift W across the N half of the basin through late Tue and inland across Texas, while the frontal boundary sinks S , but remains draped across the N end of trough, allowing the front to sink farther S across E portions of the Gulf and eventually take a NW to Se alignment. Strong NE to E winds will prevail N of this boundary and spread gradually W with the sfc trough to raise seas to 7-11 ft across much of the N 2-3rds of the basin by Tue. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... Numerous showers and thunderstorms continue across the NW Caribbean, supported by the mid to upper low over the Gulf described above, while weak troughing extends southward along the E coast of the Yucatan to the Gulf of Honduras. A tropical wave is in the central Caribbean and continues to interact with an upper level low over Haiti and the Windward Passage to support numerous showers and scattered thunderstorms across the central Caribbean, from the N coast of Colombia to Hispaniola, with more isolated activity across Puerto Rico and the Virgin Islands. This tropical wave and accompanying upper low will move westward, reaching the western Caribbean Mon, then reaching Central America by mid- week. Mainly moderate E to SE flow and seas of 4 to 6 ft dominate the basin, except 1 to 3 ft seas in the SW Caribbean where SE winds are gentle. Little change is expected for the next several days, except in the eastern Caribbean where a tropical wave currently along 46W will move into the area early Wed. Moderate E to SE trades in the wake of the current tropical wave will freshen and become Ely by Tue in advance of the next wave. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A cold front extends from 31N69W to low pres near 29N72W 1011 MB TO 27.5N76W TO N FL near 29N81.5W. High pres building in from the N behind the front has induced strong to near gale force winds offshore of NE FL and coastal GA where gale warnings are in effect for frequent gale gusts through 18Z. 00Z and 06Z models did not suggest continuation of the near gales beyond that. A strong pres gradient is also present N and NW of the low along the front and have issued a gale warning for the NW semicircle in anticipation of those winds occurring briefly, and also through 18Z. However a partial ASCAT pass across the W half of low suggests that winds aob 30 kt there. A weakening ridge prevails SE of the front, while the N extension of the tropical wave moving through the central Carib is moving across the SE waters and just E of the upper low over Haiti, supporting scattered showers and thunderstorms S of 23N and E of 70W. The front will sink S through Mon while the low along it weakens and shifts SE along it before dissipating by 36-48 hrs. High pressure building S into the region behind the front will produce fresh to strong NE to E winds N of the front and bridge modestly across it and into the NW half of the Bahamas through Tue, when the front will reach along about 27N. A broad area of 8 to 10 ft seas will build behind the front with areas of 11-13 ft and higher shifting SW and into the Nw Bahamas. These conditions to persist across the NW half of the basin through mid-week, with mainly moderate NE to E flow and 5 to 8 ft seas elsewhere S of the frontal boundary. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... None. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W... Gale Warning today. .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... Gale Warning today. $$ *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 Stripling. National Hurricane Center.