000 AXNT20 KNHC 210559 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1259 AM EST Fri Dec 21 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 0000 UTC surface analysis and satellite imagery through 0515 UTC. ...SPECIAL FEATURES... ...GALE WARNING GULF OF MEXICO... A large area of gale force wind is behind a vigorous cold front. Strong to gale force winds will progress eastward through the Gulf by Fri evening. Areas north of 23N between 83W-95W are forecast to experience gale force winds. Seas across portions of the central Gulf will build to 16 ft tonight and as high as 20 feet Friday. Please read the HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...for more details. ...GALE WARNING ATLANTIC OCEAN... S to SW gale force winds are in the western Atlantic in advance of a cold front. The area of gales is presently N 0f 27N W of 77W with seas 9 to 15 ft. The area will expand and seas build tonight through Fri evening as the cold front progress eastward through the waters. Please read the HIGH SEAS FORECAST...MIAHSFAT2/FZNT02 KNHC...for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through southern Liberia near 06N10W to 05N16W. The ITCZ continues from that point to 02N30W to the coast of Brazil near 01S45W. Isolated moderate convection is from 02N- 05N between 09W-29W. Scattered moderate convection is from 00N- 04N between 29W-50W. GULF OF MEXICO... As of 21/0300 UTC, a 994 mb low is centered over S Georgia near 32N85W. A cold front extends S from the low to the E Gulf of Mexico near 27N83W to W Cuba near 22N85W. A prefrontal trough extends from the Straits of Florida near 25N80W to W Cuba near 23N81W. Scattered moderate convection is within 60 nm of the prefrontal trough. Radar imagery shows scattered showers are elsewhere N of 23N and E of 90W. The strong cold front will continue eastward across the eastern gulf waters overnight into Fri preceded by lines of tstms, and followed increasing winds and building seas. Strong to gale force winds will shift E across the entire Gulf of Mexico overnight and on Fri, diminishing from the W, with the gale conditions ending across the Straits of Florida late Fri. Maximum seas of 20 ft on Fri will subside to less than 8 ft by late Sat. Post-frontal high pres will shift eastward across the central gulf on Sat, and move across the Florida Panhandle on Sun, leaving a ridge from the Florida Big Bend to SE Texas on Mon. Fresh return flow will set up across the NW waters on Tue. CARIBBEAN SEA... As of 21/0300 UTC, a cold ront extends from W Cuba near 22N85W to Belize near 18N88W. A prefrontal trough extends from W Cuba near 23N81W to beyond the Cayman Islands near 19N85W. Scattered moderate convection is within 60 nm of the prefrontal trough. Observations from Havana Cuba registered wind gusts near 50 knots with the surface trough. An upper level ridge axis extends from the S Bahamas to N Colombia. Scatterometer data depicts moderate to fresh winds south of Jamaica into NW Colombia. Convection is very limited as upper level ridge remains in control. Scattered showers are noted along the coast of northwest portion of Colombia into Panama and Costa Rica. Most of these showers are associated with the surface trough extending into the Pacific. Fresh to locally strong winds will continue across the south- central Caribbean through Tue, increasing to near gale force along the NW coast of Colombia during the overnight hours. Strong southerly flow will continue over the NW Caribbean ahead of a cold front across the Yucatan Channel. The front will reach from the Windward Passage to Costa Rica on Sat morning, then drift S and gradually dissipate through Sun. Strong northerly winds are expected W of the front on Fri and Fri night, increasing to near gale force along the coast of Nicaragua. ATLANTIC OCEAN... A prefrontal trough is over the W Atlantic from 32N77W to the Straits of Florida near 25N80W. Scattered moderate convection is within 60 nm of the prefrontal trough to include over the N Bahamas. A stationary front is over the central Atlantic from 32N39W to 24N60W to 27N70W. Scattered moderate convection is within 60 nm of the front N of 29N. A surface trough is along 52W/53W from 13N-24N. Rainshowers are within 120 nm of the trough. Gale force southerly flow is over the W Atlantic ahead of a strong cold front moving off the the SE United States coast preceded by lines of tstms. The cold front will reach from near 30N75W to central Cuba early Fri, from 30N72W to eastern Cuba on Fri evening, weaken from Bermuda to the Windward Passage on Sat, then stall from 27N65W to eastern Cuba on Sun. Remnants of the front will drift NW on Mon and Tue. Winds and seas will diminish across the region Sat and Sun. For additional information please visit http://www.hurricanes.gov/marine $$ Formosa