000 AXNT20 KNHC 282358 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 705 PM EST WED DEC 28 2016 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 1800 UTC surface analysis and satellite imagery through 2315 UTC. ...SPECIAL FEATURES... ...Gulf of Mexico Gale Warning...A cold front is expected to move into the northwest Gulf Thursday with strong northwest winds and building seas over the west/central Gulf Thursday night sliding south to the southwest Gulf early Friday. These winds are expected to be below gale force by Friday night. Please see the High Seas Forecast under AWIPS/WMO Headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The Monsoon Trough extends south of southwest Africa along 2N to 2N6W where the ITCZ begins and continues along 1N15W 3N26W to 2N44W, then resumes near 10N42W to 9N60W. Clusters of scattered moderate to isolated strong convection are from 5N to south of the equator between 34W-43W. ...DISCUSSION... GULF OF MEXICO... An upper ridge extends from the east Pacific region across Mexico and the south CONUS covering the Gulf of Mexico. At the surface is a surface ridge covering the Gulf and anchored by a 1022 mb high off the Florida coast near 29N83W. A weak surface trough is in the southwest Gulf south of 22N along 94W generating isolated showers within 60 nm either side of the trough. The remainder of the Gulf is under fair weather this evening. A cold front is expected to enter the Gulf on Thursday followed by strong northwest winds and building seas. These winds will increase to gale force Thursday night into early Friday. See Special Features above. The front will quickly move over the central and eastern Gulf through early Friday. High pressure in the wake of the front will shift eastward along 31N through Saturday night. CARIBBEAN SEA... An upper ridge extends from South America across Colombia and the Caribbean to east Cuba. Easterly trade winds are banking scattered showers over the southwest Caribbean south of 15N west of 90W to over Central America. Mostly fair weather with possible isolated showers are across the remainder of the Caribbean this evening. The west Atlantic surface ridge is giving the Caribbean fresh to strong trade winds that will continue through this evening. Winds will diminish later tonight through Friday night as the surface ridge weakens. A cold front is expected to move into the northwest Caribbean Friday night. The front will then stall from the Windward Passage to the Gulf of Honduras by Saturday night. HISPANIOLA... A weak surface trough extends from the southwest Atlantic to the north coast of Hispaniola generating isolated showers over portions of the Dominican Republic with fair weather across the remainder of the island this evening. Possible isolated showers will continue across the island through Friday increasing early Saturday with the approach of the cold front that will stall over the Windward Passage Saturday night. ATLANTIC OCEAN... A shortwave upper trough extends through 32N68W to the Turks and Caicos supporting a surface trough that extends from 32N68W to 26N70W. This surface trough splits a surface ridge that covers the Far west Atlantic into the Gulf of Mexico and a larger surface ridge that covers the central Atlantic anchored by a 1026 mb high near 31N49W. A second weaker surface trough is to the south extending along 71W south of 23N across the Turks and Caicos to the north coast of Hispaniola generating isolated showers within 90 nm either side of the surface trough. An upper trough over the east Atlantic is supporting a cold front that extends through 32N25W to 22N34W then dissipates to 20N52W. An east/west upper ridge extends across the tropics along 9N/10N and is advecting tropical moisture with possible scattered showers within a 200 nm swath from 10N46W along 20N33W to Africa near 21N17W. The west Atlantic surface ridge will persist through Thursday night. A cold front will move off the northeast Florida coast Thursday evening reaching from Bermuda to central Cuba Friday evening and from 32N54W along 24N65W to the Windward Passage Saturday evening. Strong high pressure behind the front will shift eastward along 31N through Saturday night. For additional information please visit http://www.hurricanes.gov/marine $$ PAW