000 AXNT20 KNHC 152337 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 637 PM EST Fri Dec 15 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 1800 UTC surface analysis and satellite imagery through 2330 UTC. ...SPECIAL FEATURES... ...Gale Warning in the Gulf of Mexico... A cold front extends across the northern Gulf of Mexico from 30N83W to 27N90W to 21N97W. Gale-force northwesterly winds are occurring mainly south of 25N and west of the front, with seas ranging from 8 to 10 ft. These conditions are expected through at least the next 12 hours as the front progresses across the basin and the pressure gradient relaxes. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...Gale Warning in the Caribbean Sea... A strong high pressure will build to the north of the Caribbean Sea during the evening today. A tight pressure gradient has developed in the south central Caribbean supporting fresh to strong trades. Gale-force winds will develop along the northwest portion of the Colombian coast each night starting tonight through early Monday. The sea heights will build to 10-13 feet in this area. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough passes through the coastal sections of Liberia near 07N12W to 06N15W. The ITCZ continues from 06N15W to 04N40W. Scattered moderate convection is from 04N-10N between 13W-36W. ...DISCUSSION... GULF OF MEXICO... A cold front stretches from the Florida Big Bend near 30N84W to 27N90W to the northeast Mexico coast near 21N97W. Gale-force winds are noted west of the front and mainly south of 25N. Please refer to the Special Features section above for details. Scattered showers are observed northwest of the front north of 26N and west of 90W. Fair weather prevails elsewhere with light to gentle easterly winds, as noted in scatterometer data. Expect for the front to continue moving southeast across the basin through the next 12-18 hours. By then, the front will stall and weaken. A warm front will develop from this frontal boundary by late Saturday, moving north with convection. These conditions will continue through the weekend. CARIBBEAN SEA... Gale-force winds are expected to develop over the south-central Caribbean within the next 12 hours. These conditions will continue through the weekend. Please refer to the Special Features section above for details. A surface trough is in the coastal waters of Central America south of 18N and along 83W. Scattered showers are observed along the front from 14N-17N. Another surface trough extends across eastern Cuba from 20N79W to 21N76W. This boundary is the remnants of a stationary front. No significant convection is related to this feature at this time. Fair weather prevails across the remainder of the basin, with gentle to moderate trades. Little change is expected through the next 24-48 hours. ...HISPANIOLA... Fair weather prevails across the island. Isolated showers could develop this weekend over the area due to orographic lifting and daytime heating. ATLANTIC OCEAN... Fair weather prevails across the western Atlantic ahead of a frontal boundary currently located along the Georgia/South Carolina coastlines. To the east, a surface trough extends from 29N53W to 23N66W to 21N76W. Another trough is located from 25N46W to 20N47W. The remainder of the area is under the influence of a surface ridge, anchored by a 1034 mb high centered near 36N30W, and a 1022 mb high located near 28N61W. Expect for the cold front over the southeast CONUS to move offshore over the west Atlantic waters. The surface high over the southwest Atlantic will strengthen during the weekend. The pressure gradient generated in this area will trigger the Caribbean gale-force winds this weekend. For additional information please visit http://www.hurricanes.gov/marine $$ ERA