000 AXNT20 KNHC 201150 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 649 AM EST Fri Jan 20 2017 Tropical Weather Discussion for North America, Central America Gulf of Mexico, Caribbean Sea, northern sections of South America, and Atlantic Ocean to the African coast from the Equator to 32N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0600 UTC surface analysis and satellite imagery through 1130 UTC. ...SPECIAL FEATURES... A cold front is over the western Atlantic from 32N53W to 25N57W to 23N65W moving east at 10 to 15 kt. Winds reaching gale force are noted north of 28N, within 180 nm both ahead of the front and following the front. The gales will persist into the afternoon, before diminishing late in the day. See latest NWS High Seas Forecast under AWIPS/WMO headers HSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the African coast near 06N11W to 05N11W. The intertropical convergence zone continues from 05N11W to the coast of South America near 02S42W. Scattered moderate isolated strong convection is observed within 120 nm either side of the ITCZ between 18W and 33W. ...DISCUSSION... GULF OF MEXICO... A vigorous short wave trough in the mid levels of the atmosphere was supporting a squall line across the northern Gulf of Mexico at 06 UTC. Strong thunderstorms along the squall line have since disspated, leaving mostly lower to mid level cloudiness across the northeast Gulf. Areas of fog reducing visibility to 3 to 5 nm are noted in various offshore platforms in the northwest Gulf. A somewhat tight pressure gradient between 1017 mb high pressure centered over the Bahamas and a surface trough over central Mexico was allowing moderate to fresh southerly winds over the south- central Gulf of Mexico, as noted in a 06 UTC scatterometer pass. Elsewhere gentle to moderate south the southeast winds persist with 2 to 4 ft seas. Showers and thunderstorms will accompany a strong cold front forecast to move into the northwest Gulf Saturday night, reaching from southeast Louisiana to near Tampico Mexico by Sunday morning, and from the Florida Big Bend to the Yucatan Peninsula by Sunday evening. Strong to gale force winds are possible behind the front Sunday through Monday across the northern and central Gulf, possibly spilling into the southeast Gulf, with seas building as high as 16 to 19 ft. Conditions will gradually improve from west to east Monday night through Tuesday night as high pressure builds in behind the front. CARIBBEAN SEA... 1017 mb high pressure centered over the central Bahamas is maintaining generally light to gentle anticyclonic flow across the north central and northeast Caribbean and Tropical North Atlantic regions. Seas are 3 to 5 ft in these areas. Fresh trade winds are noted off the central coast of Colombia, and over the Gulf of Honduras between the high pressure to the east and troughing over southern Mexico. Trade wind flow will diminish over the south central Caribbean through early next week as the high pressure weakens and shifts east ahead of an approaching cold front. The front is forecast to reach the Yucatan Channel and the northwest Caribbean Sunday night, accompanied by strong winds and building seas. The front will reach from the Windward Passage to the eastern coast of Nicaragua Monday night, with strong southwest winds expected near the Windward Passage just ahead of the front. Over the tropical north Atlantic waters, expect continued mainly gentle to moderate trade winds and seas of 4-6 ft. ...HISPANIOLA... Deep layer subsidence will support dry conditions with light to gentle breezes for the next couple of days with partly cloudy skies and little to no shower activity. ATLANTIC OCEAN... A weak 1017 mb high is centered over the central Bahamas near 24N75W. Scattered showers and thunderstorms are evident within 150 nm ahead of the cold front from 32N53W to 25N57W to 23N65W. 1025 mb high pressure is centered near 32N29W, supporting moderate to fresh trade winds across the Azores and from 15N to 20N between 20W and 27W. For additional information please visit http://www.hurricanes.gov/marine $$ CHRISTENSEN