000 AGXX40 KNHC 120722 MIMATS Marine Weather Discussion NWS National Hurricane Center Miami FL 222 AM EST Tue Dec 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... High pressure over the W central Gulf controls the weather across the basin, while a developing cold front is located to the NW-N moving into the lower Mississippi Valley states. Gentle winds are across the central Gulf under an eastward extending ridge axis from the high, and mainly moderate winds elsewhere, except in the N central Gulf where the pressure gradient is locally tighter. Seas are mainly 1-3 ft, except up to 4 ft near the Straits of Florida and Yucatan Channel. The high will shift eastward as the developing cold front approaches and enters the N central and NE Gulf shortly after sunrise this morning. Winds will shift to W-NW while increasing to fresh to strong behind the front, with seas building to 8 ft as a result through the afternoon. The front will continue to race SE extending from near Fort Myers, Florida to the central Gulf along 25N by this coming evening. The front will move SE of the basin through Wed morning with high pressure re-building in its wake. A ridge axis will again extend across the central Gulf by Wed evening with winds gentle and 1-3 ft across the basin, except 4-5 ft in the SE portion due to residual NW swell behind the front. The ridge will shift eastward ahead of the next cold front which is forecast to move into the NW waters by Thu evening. This next front will also race SE extending from the Florida Panhandle to the central Gulf near 26N91W to near Tampico, Mexico by Fri morning, from SW Florida to Veracruz, Mexico Fri evening, exiting the basin to the SE by Sat evening. Winds will shift to NW-N and increase to fresh to strong with seas building to 5-8 ft behind the front. Conditions will improve by Sat morning as high pressure settles across the southern U.S. Gulf coast states. The high will then slide eastward for the end of the weekend allowing for return flow to dominate the basin ahead of the next potential cold front. ...CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... A stationary front extends from near the Windward Passage to just SE of Jamaica to western Panama. Active convection remains near the boundary S of Jamaica and W of the front. A recent scatterometer pass showed fresh to near gale force northerly winds W of the front to around 18N83W, with seas of 7-11 ft. Meanwhile, moderate trades and 2-4 ft seas prevail E of the front, except 4-7 ft W of 72W. The front will remain nearly stationary through mid-week while gradually dissipating to a remnant trough by the end of the week. The fresh to strong winds will persist just W of the front, finally diminishing Thu as the front dissipates. Once the front dissipates, the pressure gradient will tighten allowing for fresh to strong trades in the S central Caribbean by Thu evening, strongest to near gale force just NW of the coast of Colombia by Fri night. The pressure gradient will continue to tigthen during the upcoming weekend with gale conditions possible NW of the coast of Colombia by Sat night. Meanwhile, another cold front will approach the NW Caribbean by Wed afternoon, but will likely dissipate before it makes much progress into the basin. The next cold front after that is forecast to move into the NW portion Fri night, stalling and gradually dissipating from near eastern Cuba to the Gulf of Honduras during the upcoming weekend. ...SW N ATLANTIC INCLUDING THE BAHAMAS... A stationary front extends from near 27N65W to across the Turks and Caicos to the Windward Passage, with a ridge axis analyzed from SE Florida to 1018 mb high pressure near 31N70W. A recent scatterometer pass showed fresh to locally strong N-NE winds just W of the front to the S of 27N, with gentle to moderate winds near the ridging. Seas are 6-8 ft in the area of stronger winds, with 3-5 ft elsewhere across the basin outside of the Bahamas. Meanwhile, SW flow is developing offshore of NE Florida ahead of the next cold front. That next front will continue to approach through the morning and afternoon, with SW flow increasing to fresh to strong during the afternoon. The front will move into the NW waters by this coming evening with winds increasing to near gale force, with a gale warning in effect from 31N northward. Shifting W-NW strong to near gale force winds will also follow the front, spreading across the entire waters N of 27N tonight. The front will extend from near Bermuda to the Straits of Florida by early Wed afternoon with conditions improving under ridging in its wake. The ridge will extend from SE Florida to 27N70W Wed night before weakening as the next cold front approaches by Thu morning. Fresh to strong winds will precede the next front N of 29N by Thu morning, but will diminish through the day as this next front remains primarily N of 31N. A stronger front will approach by Fri morning with SW flow increasing back to fresh to strong N of 27N by Fri afternoon. That front will move into the NW waters by Fri evening with winds both ahead of and behind the front possibly increasing to gale force. That front will race eastward extending from near 31N68W to central Cuba by Sat morning, then dissipating as it lies down from near 25N65W to eastern Cuba late Sat night. $$ .WARNINGS...Any changes impacting coastal NWS offices will be coordinated through AWIPS II Collaboration Chat, or by telephone: .GULF OF MEXICO... None. .CARIBBEAN SEA AND TROPICAL N ATLANTIC FROM 07N TO 19N BETWEEN 55W AND 64W... .AMZ031...CARIBBEAN FROM 11N TO 15N BETWEEN 72W AND 80W INCLUDING COLOMBIA BASIN... GALE CONDITIONS POSSIBLE Sat night. .SW N ATLANTIC INCLUDING THE BAHAMAS... .AMZ111...ATLANTIC FROM 27N TO 31N W OF 77W... GALE CONDITIONS POSSIBLE Fri night. .AMZ113...ATLANTIC FROM 27N TO 31N BETWEEN 70W AND 77W... GALE CONDITIONS POSSIBLE Fri night. .AMZ115...ATLANTIC FROM 27N TO 31N BETWEEN 65W AND 70W... GALE CONDITIONS POSSIBLE Fri night into Sat. $$ *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 Lewitsky. National Hurricane Center.