000 AXNT20 KNHC 150933 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 433 AM 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... ...Gale Warning Gulf of Mexico... As of 0600 UTC a cold front extends from southern Alabama SW to SE Louisiana to NE Mexico near 24N97W. Northerly fresh to strong winds are behind the front and will rapidly increase to near-gale force through sunrise today when minimal gale-force winds are expected to develop offshore of Mexico. Seas will build to 8 ft in the area with the highest winds. These conditions are forecast to diminish by sunrise on Saturday. See the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...Caribbean Gale Warning... Strong high pressure will build north of the Caribbean during the evening today resulting in a tight pressure gradient in the south central basin where trades will increase to fresh to strong. A strong pressure gradient will persist during the weekend allowing for the development of gale-force winds northwest of the Colombian coast starting tonight through early Monday. Seas will build to 13 ft in this area. See the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...ITCZ/MONSOON TROUGH... The monsoon trough extends from the west coast of Africa near 06N11W to 05N16W where the ITCZ continues along 05N30W to 04N41W to 0N50W. Scattered moderate convection is observed from 01N-08N between 08W and 36W. ...DISCUSSION... GULF OF MEXICO... Weak surface ridging prevails across the SE Gulf ahead of a cold front that at 0600 UTC extends from southern Alabama SW to SE Louisiana to NE Mexico near 24N97W. Northerly fresh to strong winds are behind the front and will rapidly increase to near-gale force through sunrise today when minimal gale-force winds are expected to develop offshore of Mexico. Looking ahead, the cold front will reach from the Florida Big Bend area in the northeast Gulf to near Tampico Mexico tonight. The front will stall from Tampa to the Bay of Campeche on Saturday before lifting back to the northwest through Sunday. Scattered showers are in the NW Gulf continuing through tonight. See the Special Features section for further details. CARIBBEAN SEA... Shallow moisture associated with the remnants of a former stationary front support isolated showers over the NW Caribbean. In the SW basin, a surface trough extends from 18N80W to 09N81W supporting similar shower activity W of 80W. Middle to Upper level ridging and dry air subsidence support stable conditions elsewhere. Strong high pressure will build north of the Caribbean this evening resulting in a tight pressure gradient in the south central basin. This scenario will continue through the weekend allowing for the development of gale-force winds northwest of the Colombian coast starting tonight through early Monday. See the Special Features section for further details. ...HISPANIOLA... Cloudiness prevail mainly over SW Dominican Republic due to the proximity of a nearly stationary trough in the SW N Atlc extending to eastern Cuba. Isolated showers are possible mainly over higher terrain through later this morning. Then, moisture will diminish as the trough continues to weaken. ATLANTIC OCEAN... Strong surface high pressure anchored south of the Azores extends a ridge axis into SW N Atlc waters as well as the central and eastern Atlc. A weakness in the ridge, remnant of a former stationary front, is analyzed as a surface trough from 30N54W SW to the southern Bahamas to eastern Cuba. Isolated showers are within 120 nm either side of this boundary. A cold front will move off the northeast Florida coast this evening, reach from Bermuda to south Florida Saturday, then will stall and gradually dissipate along 25N through early next week as high pressure from the southeast United States builds eastward across the area. For additional information please visit http://www.hurricanes.gov/marine $$ Ramos