000 AXNT20 KNHC 231832 AAA TWDAT Tropical Weather Discussion...Updated NWS National Hurricane Center Miami FL 1227 PM EST Sat Dec 23 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. Updated Special Features Section for Colombia Gale Warning Based on 1200 UTC surface analysis and satellite imagery through 1715 UTC. ...Gale Warning in the Gulf of Mexico... As of 1500 UTC, a cold front extends from SE Louisiana to near Tampico, Mexico, that is reporting strong northerly winds with gusts up to 38 kt. A recent scatterometer pass confirmed the presence of gale force winds behind the cold front, across the west-central Gulf, near Tampico. These winds will spread southward near Veracruz later today. The front will reach from the Mississippi Delta to the western Bay of Campeche this evening, then slow from the Florida Panhandle to the Eastern Bay of Campeche early Sun as a secondary cold front surges S into the northern waters reaching from Straits of Florida to near Veracruz, Mexico on Mon night. Fresh to strong N-NE winds will follow the secondary front Sunday night into Monday with seas of 6-7 ft, mainly across the north and SW Gulf waters. By Monday night, gentle to moderate easterly winds will dominate most of the Gulf region with seas of 4-6 ft. Please read the latest NHC High Seas Forecast under AWIPS/WMO headers MIAHSFAT2/FZNT02 KNHC for more details. ...Gale Warning for the coast of Colombia... High pressure over the western Atlantic and Florida peninsula is shifting southward, tightening the pressure gradient over the south central and southwest Caribbean Sea. An earlier scatterometer satellite pass indicated winds to 30 kt off the coast of Colombia. This pattern will allow winds pulse to minimal gale force off the coast of Colombia tonight and Sun night. The high pressure will weaken Mon, but still will maintain strong trades over the Central and SW Caribbean through Wed, with near gale force nocturnal winds near the coast of Colombia. ...ITCZ/MONSOON TROUGH... The monsoon trough enters the Atlantic Ocean through Nigeria and and continues to 04N at the Prime Meridian to 04N17W. The ITCZ axis extends from 04N17W to 03N30W to 03N45W to NE Brazil near 02N51W. Scattered moderate convection is south of the monsoon trough to the Equator between the Prime Meridian and 20N. Similar convection is noted N of the ITCZ axis from 04N-06N between 23W- 35W. ...DISCUSSION... GULF OF MEXICO... A cold front is moving across the Gulf waters. Please, see Special Features section for details. E of the front, a ridge from the Atlantic Ocean extends across Florida into the eastern Gulf of Mexico, and provides a gentle to moderate southerly return flow E of 90W while a tighter pressure gradient in the western part of the Gulf, ahead of the front, supports moderate to strong southerly winds. The aforementioned ridge will continue to bring mostly clear skies, light winds, and warm temperatures across South Florida the remainder of the weekend. On Monday, a cold front will move across South Florida and the Florida Keys. CARIBBEAN SEA... Latest scatterometer data continue to show fresh to strong winds across the central Caribbean, while moderate to fresh NE winds persist across the Windward Passage. An altimeter pass indicated seas of 11-12 ft with the strongest winds near the coast of Colombia. Patches of low level clouds, embedded in the trade wind flow, are producing isolated to scattered passing showers over Hispaniola, Puerto Rico and the Lesser Antilles. Showers carried by the trades are aslo affecting the ABC Islands and parts of Central America, including the Gulf of Honduras. High pressure N of the area will maintain strong trades over the Central and SW Caribbean through Wed, with near gale force nocturnal winds near the coast of Colombia. Fresh to strong NE winds are expected through the Windward Passage as well. Large E swell will build seas to 9 ft E of the Lesser Antilles on Mon night, with these swells reaching the E Atlantic passages on Tue evening. At that time, expect building seas to 10 ft. ...HISPANIOLA... Low-topped trade wind showers will continue to move across the island the remainder of the weekend. High pressure over the Atlantic will continue to support pulses of fresh to locally strong winds across the Windward Passage through Sunday. ATLANTIC OCEAN... A ridge dominates the western Atlantic, including the Bahamas and the State of Florida. A frontal trough extends from a very weak low pressure of 1023 mb located near 31N55W to 24N54W to the near the Leeward Islands. These features are forecast to dissipate over the next 12-24 hours. Isolated to scattered showers are along the trough axis. E of the frontal trough, a strong 1039 mb high pressure centered just E of the Azores extends a ridge across the remainder of the Atlantic. The pressure gradient between this strong high pressure and lower pressure in the vicinity of the monsoon trough/ITCZ is supporting fresh to strong winds mainly N of 11N between the coast of Africa and 40W, with seas of up to 12 ft based on altimeter data. This high pressure has displaced the monsoon trough/ITCZ farther south. The next cold front will move off the NE Florida coast on Sun evening, and stall from near Bermuda to Central Cuba by Tue. For additional information please visit http://www.hurricanes.gov/marine $$ GR/Christensen