000 AXNT20 KNHC 210007 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 707 PM EST Thu Dec 20 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 1800 UTC surface analysis and satellite imagery through 2345 UTC. ...SPECIAL FEATURES... ...GALE WARNING GULF OF MEXICO... A large area of gale force wind is expected to develop in the Gulf of Mexico this afternoon along and behind a vigorous cold front. Strong to gale force winds will progress eastward through the Gulf by Fri evening. Areas north of 23N between 81W-95W are forecast to experience gale force winds. Seas across portions of the central Gulf will build to 14 ft by this afternoon and as high as 21 feet tonight and Friday. ...GALE WARNING ATLANTIC OCEAN... S to SW gale force winds are expected in the western Atlantic in advance of a cold front. The area of gales will expand tonight into early Fri 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 04N08W to 03N13W. The ITCZ continues from that point to 01N29W to 02N41W. Scattered moderate convection is observed from 03N to 00N between 35W-45W. Elsewhere, scattered showers are noted along and within the ITCZ and monsoon trough. GULF OF MEXICO... A cold front extends from a 997 mb low pressure center at 30N87W to 26N87W in the central part of the Gulf of Mexico. Then, enters the Yucatan peninsula near 21N88W and continues into Mexico. A pre-frontal surface trough is within 180 nm to 200 nm to the east of the cold front. Most of the stronger convection is associated with this pre-frontal trough. Numerous moderate isolated strong convection runs right along the pre-frontal surface trough from 31N80W to Fort Myers near 26N82W to the western coast of Cuba near 20N86W. Broken to overcast multilayered clouds and other possible scattered thunderstorms are seen in the vicinity of the cold front. A second surface trough is also observed west of the cold front from 29N90W to 24N91W. Scattered convection is noted 60 to 90 nm west of this surface trough. The strong cold front will move E across the eastern gulf waters overnight preceded by lines of tstms and followed by large seas. Strong to gale force winds will spread E across the entire Gulf of Mexico overnight, then diminish from the W with the gale conditions diminishing across the Straits of Florida late Fri. Seas are forecast to subside to less than 8 ft by late Sat. High pres will shift eastward across the central gulf on Sat, then 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... A pre-frontal surface trough extends 180 to 200 nm to the east of a cold front over the Gulf of Mexico. The tail end of the trough enters the western Caribbean waters from western Cuba to the Yucatan peninsula. Scattered modearte isolated strong convection is noted from 22N82W to 20N84W. Observation in Habana registered wind gust near 50 knots ahead of the surface trough. An upper level ridge extends from northeast Bahamas to Colombia and NW Venezuela. 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 entering the Yucatan Channel overnight. The front will reach from the Windward Passage to Costa Rica by 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 cold front passes through 32N38W transitions to stationary front near 31N42W to 24N60W to 26N69W. Scattered moderate convection from 32N38W to 26N39W. Scattered convection is also observed from 26N to 16N between 20W-33W. One surface trough is along 44W/43W from 23N to 14N. Rainshowers are possible along the vicinity of the trough. A second surface trough is along 51W/53W from 23N to 10N. Rainshowers are possible within the the vicinity of the trough. Near gale to gale force southerly flow is developing W of 75W and N of 27N to the E of 75W 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 west- central Cuba early Fri, from 30N72W to eastern Cuba on Fri evening, weaken from Bermuda to the Windward Passage on Sat, then become stationary from 27N65W to eastern Cuba on Sun. Winds and seas will diminish across the region Sat and Sun. For additional information please visit http://www.hurricanes.gov/marine $$ MTorres