867 AXNT20 KNHC 180522 RRA TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Mon Dec 18 2023 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 31N. The following information is based on satellite imagery, weather observations, radar and meteorological analysis. Based on 0000 UTC surface analysis and satellite imagery through 0520 UTC. ..SPECIAL FEATURES... Western Atlantic Gale Warning: A cold front extends from 988 mb low pressure located along the South Carolina coast to 25N76W to central Cuba near 21N78W. A warm front extends from the low to near 23N66W. A tight pressure gradient between a ridge extending SW from strong high pressure of 1046 mb near 43N51W and the area of low pressure is supporting gale force winds over the western Atlantic waters. Seas in this area are up to 20 ft. A large area of 12 ft seas has been generated by this system, with seas greater than 12 ft over the waters N of 23N and W of 66W. The low will rapidly track further northeastward along the Atlantic coast tonight, with gale force winds shifting N of the area by Tue morning. The area of 12 ft seas will shift eastward, merging with another area of large swell generated from gales over the central Atlantic. Central Atlantic Gale Warning: Strong high pressure will continue to build over the north central Atlantic. This will continue to tighten the pressure gradient between this area of high pressure and a surface trough, which will support gale force winds over the discussion waters N of 26N between 42W and 55W tonight. Seas will build over these waters, with seas greater than 12 ft spreading southward and westward, merging with the area of 12 ft seas generated from the gale force winds over the western Atlantic waters through the middle of the week. The area of high pressure will shift further from the area, loosening the pressure gradient across the central Atlantic waters diminishing winds below gale force Tue. Please read the latest NWS High Seas and Offshore Waters Forecasts issued by the National Hurricane Center at https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml and https://www.nhc.noaa.gov/marine/offshores.php for more details on both Gale Warnings. ...MONSOON TROUGH/ITCZ... The monsoon trough enters the Atlantic near 08N13W, then extends westward to near 08N17W. The ITCZ continues westward from 08N17W to 07N25W to 03N35W to 05N44.5W. Scattered moderate convection is Depicted from 01N to 09N between 18W and 33W. ...GULF OF MEXICO... Please read the Special Features section above about an ongoing Gale Warning. A dissipating cold front extends from the Florida Panhandle to the Yucatan Peninsula. Fresh to strong NW to N winds prevail over the eastern Gulf in association with the pressure gradient between the strong low pressure located in the coast of South Carolina and the pressures in the area. While, high pressure over the western Gulf is supporting NW gentle to moderate winds over the area. Seas of 8 to 12 ft prevail E of 90W. Seas of 8 to 10 ft are between 88W and 91W, and seas of 4 to 8 ft are W of 91W. For the forecast, the strong low pressure that was affecting the Gulf region is now along the coast of South Carolina, with the associated cold front moving SE across the western Caribbean. Fresh to strong NW to N winds continue across the eastern Gulf and will gradually diminish through Mon. High pressure will be in control of the weather pattern across the Gulf waters through mid-week, before strengthening high pressure N of the region will bring fresh to strong NE winds across the eastern Gulf, including the Straits of Florida. ...CARIBBEAN SEA... A cold front extends from central Cuba to NW Nicaragua. NW fresh to strong winds prevail W of 80W. E moderate to fresh winds are E of 75.5W. Light to gentle winds are elsewhere. Seas are in the 6 to 10 ft range W of 81W, reaching 11 ft in the Yucatan channel. Seas of 5 to 7 ft are elsewhere. For the forecast, a cold front is moving SE across the western Caribbean, extending from central Cuba to the far NE coast of Nicaragua. Fresh to strong NW winds follow the front. The front will reach from eastern Cuba to 10N80W Mon afternoon, and from Hispaniola near 20N70W to 10N79W Tue afternoon. Fresh to strong northerly winds and seas to 9 ft are expected in the wake of the front. Strong high pressure over the Atlantic will continue to produce fresh to locally strong winds over the NE Caribbean through tonight before diminishing. ...ATLANTIC OCEAN... Please read the Special Features section for more on the Storm and Gale Warnings. A stationary front extends southwestward from a 1020 mb low outside of our area near 35N33W to north of Puerto Rico, then continues as a warm front to a 988 mb storm center near 33N78.5W. A cold front extends from that low to central Cuba then into the NW Caribbean. Scattered moderate and isolated strong convection is N of 20N between 38W and 49W. Similar convection is depicted ahead of the cold front N of 21.5N between 70.5W and 76W. Outside of the warning areas, NE to E fresh to strong winds prevail N of 20N and W of 50W as well as N of 13N between 56W and the Lesser Antilles. Fresh to locally strong winds are found N of 19N and E of 29W. Gentle to moderate winds prevail elsewhere. Outside of the area of 12 ft seas, seas of 8 to 11 ft prevail N of 20N and W of 50W, N of 13N between 56W and the Lesser Antilles, as well as N of 19N and E of 29W. Elsewhere, seas are in the 5 to 8 ft range. For the forecast W of 55W, a cold front extends from 988 mb low pressure located along the South Carolina coast to 25N76W to central Cuba near 21N78W. SE to S gale-force winds are ahead of the front N of 26N and E of front to 68W. Behind the front, NW gales are N of 28.5N tonight. Scattered strong thunderstorms continue along and ahead of the cold front. The front is expected to reach from 31N69W to eastern Cuba by Mon afternoon, and from 31N68W to the N coast of Hispaniola near 20N70W by Tue afternoon. The front will then move slowly E into the middle of the week as high pressure builds behind it. Gales ahead of the front will persist through Mon night while gale behind the front are expected through early Mon morning. $$ KRV