000 AXNT20 KNHC 180558 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1258 AM EST SUN DEC 18 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 0600 UTC surface analysis and satellite imagery through 0515 UTC. ...SPECIAL FEATURES... A cold front will enter the western Gulf of Mexico early this morning. Strong high pressure over the plains states will drive the front quickly southward through the western Gulf today. North winds are expected to rapidly reach gale force over the western Gulf of Mexico behind the front beginning at 1200 UTC this morning. The gale-force winds will become confined to the southwestern Gulf of Mexico by tonight. Seas will build to 8 to 13 feet from these winds by this evening. Please read the Atlantic high seas forecast, that is listed under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC, for more details. The tightening pressure gradient between high pressure building north of the Caribbean and lower pressure associated with climatological low pressure over Colombia will support gale-force winds over portions of the south central Caribbean beginning 0600 UTC Monday morning, persisting until 1800 UTC Monday. Please read the Atlantic high seas forecast, that is listed under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC, for more details. ...THE ITCZ/MONSOON TROUGH... The monsoon trough extends westward from the African coast from near 08N13W to 04N23W. The ITCZ continues from 04N23W to 03N40W to 05N52W. Scattered moderate and isolated strong convection are from 01N to 15N between 11W and 22W. Scattered moderate convection is from 03N to 13N between 22W and 50W. ...DISCUSSION... ...THE GULF OF MEXICO... A ridge axis extends from high pressure over the western Atlantic across Florida and westward to the west central Gulf of Mexico. Meanwhile, low pressure over the mid Mississippi Valley supports a cold front that is rapidly approaching the Texas coast. These features support mainly moderate to fresh south to southeasterly winds over the entire Gulf basin early tonight. The cold front will cross the northwestern Gulf late tonight with Gale force winds developing northwest of the front. Please refer to the special features section regarding details of this gale event. The cold front will move quickly toward the central Gulf today and stall out from northern Florida to the southwestern Gulf late tonight. Scattered to numerous showers will also be possible along this front through tonight. ...THE CARIBBEAN SEA... Moderate to fresh trades cover much of the central and Eastern Caribbean tonight with locally strong to near-gale force winds over the south central Caribbean near the coast of Colombia and Venezuela. Moderate to fresh trades are elsewhere over the Caribbean. No deep convection is currently observed over the basin. Scattered showers are embedded in the trades streaming across the central and eastern Caribbean, including the Windward Islands. Over the next 24 hours, high pressure building north of the Caribbean will help to increase trades slightly over the Caribbean, resulting in gale-force winds developing over portions of the south central Caribbean. Please refer to the special features section for more details. ...HISPANIOLA... Deep-layer high pressure will maintain a relatively quiet weather pattern over the island for the next several days. Subsident air aloft will produce drying over the area tonight through Tuesday with only a few passing showers in the trade wind flow. ...THE ATLANTIC OCEAN... A weakening stationary front extends SW from 31N43W to 23N74W. An area of fresh to strong NE to E winds is present along and up to 120 nm north of this front. High pressure centered near the Azores will be reinforced by a new cell moving eastward from north America. The resultant ridge will continue to dominate the remainder of the Central and Eastern Atlantic through the early part of the week. For additional information please visit http://www.hurricanes.gov/marine $$ Latto