000 AXNT20 KNHC 182319 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 619 PM EST Tue Dec 18 2018 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. ...MONSOON TROUGH/ITCZ... The monsoon trough passes from N Liberia near 06N11W to 04N17W. The ITCZ continues from that point to 00N30W to 00N50W. Scattered moderate convection is noted along the ITCZ between 28W-50W. GULF OF MEXICO... An upper level low over southern NM is progressing eastward supporting diffluence across northwest Gulf of Mexico. Scattered showers associated to the upper low are observed north of 23N and west of 90W. Along the northeast Gulf, a 1021 mb surface high is centered near 30N88W. Gentle to moderate anticyclonic winds prevail across the basin. The upper-level low is forecast to intensify as it moves eastward from Texas to the Carolinas Wednesday through Thursday night, dragging a cold front across the Gulf waters. Marine conditions are expected to rapidly deteriorate across the region by Thursday afternoon as the low deepens. Gale-force winds are likely north of 25N across the central Gulf through the end of the week. Seas will build to a maximum around 20 ft on Friday over the central Gulf. CARIBBEAN SEA... A 1015 mb surface low is centered over the west Caribbean near 16N82W. A weak frontal boundary is noted to the west of the low from 18N87W to 21N78W. Scatterometer data depicts gentle to moderate trades across most of the Caribbean. Fresh to strong winds are noted south of 15N between 72W-78W. These winds will pulse every night through the period. The weakening stationary front extending from eastern Cuba to 16N85W will dissipate tonight, then drift westward over the Yucatan peninsula overnight as a surface trough. Fresh to strong winds will continue across the south-central Caribbean through the weekend, with the strongest winds near the coast of Colombia each night. A cold front associated with an intense low pressure system north of the area will enter the northwest Caribbean Thursday night. ATLANTIC OCEAN... A cold front extends across the west Atlantic from 31N55W to 27N62W. A stationary front extends from that point to 21N76W. Scattered moderate convection is noted within 75 nm east of the front and north of 27N. Surface ridging prevails across the remainder of the basin anchored by a 1025 mb high centered near 27N32W. The western portion of the frontal system in the west Atlantic will slowly drift northward Wednesday and Thursday as an intense low pressure system develops over the southeast U.S. Gale-force winds are likely north of 27N and east of Florida Thursday night through Friday night both ahead and behind of a cold front associated with the low. Maximum seas will build to around 20 ft by Friday night west of 70W. For additional information please visit http://www.hurricanes.gov/marine $$ ERA