000 AXNT20 KNHC 200544 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Mon Dec 20 2021 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... Gulf of Mexico Gale Warning: A cold front is along 28N82W 20N98W. Expect gale-force winds, and sea heights from 9 feet to 11 feet, from 22N to 26N between 96W and 97W. These conditions will last for the next 9 hours or so. A 1013 mb low pressure center will develop near 25N94W. A cold front will extend from the low pressure center toward the south/southwest. Expect gale-force winds, and sea heights that will range from 10 feet to 13 feet, from 22N to 24N between 95W and 97W. The forecast situation at 24 hours will consist of a cold front, that will extend from a 1011 mb low pressure center that will be near 26N89W, to 18N93W. Expect gale-force winds, and sea heights that will range from 8 feet to 10 feet, from 19N to 24N between 92W and 97W, including within 60 nm of Veracruz in Mexico. Please, refer to the latest High Seas Forecast, that is issued by the National Hurricane Center, at the following website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml, for more details. Atlantic Ocean Gale Wind Warning from 35W eastward: Gale-force winds are forecast in the area that is called IRVING. An Azores low pressure center and two frontal boundaries are to the north of 25N from 31W eastward. These conditions are expected to continue until 21 December at 00 UTC. Please, refer to the Meteo-France High Seas Forecast, on the following website, http://www.gmdss.org/bulletins/METAREA2.HIGH_SEAS_WARNING.1956.19 1956225601.html, for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Liberia near 06N11W, to 05N19W. The ITCZ continues from 05N19W, to 04N23W and 04N36W. A surface trough is along 39W/40W from 06N toward the Equator. Precipitation: scattered moderate to widely scattered strong is within 180 nm to the north of the ITCZ between 25W and 31W. Widely scattered moderate to isolated strong is within 180 nm to the south of the monsoon trough from 15W eastward, and within 180 nm to the north of the monsoon trough and the ITCZ between 17W and 25W. ...GULF OF MEXICO... Please, read the SPECIAL FEATURES section, for information about the current cold front and associated gale-force winds, and a developing low pressure center and its associated gale-force winds. Precipitation: broken to overcast multilayered clouds, and scattered moderate to isolated strong, are to the north of the current cold front. Scattered moderate to widely scattered strong is in parts of the Yucatan Peninsula. A cold front from near Tampa Bay to just N of Veracruz, Mexico, will stall tonight as low pressure begins to form along it in the western Gulf. The low will then track NE through the northern Gulf through Tue, with the cold front dragging eastward to the south of it. Gale force winds offshore Tampico, Mexico will continue tonight, then gradually move NE to the north and west of the low pressure on Mon. Elsewhere behind the front, strong NW winds can be expected. Winds and seas will subside Wed through Thu in the wake of the front, as weak high pressure builds in across the Gulf. ...CARIBBEAN SEA... The tight pressure gradient between a 1022 mb west central Atlantic Ocean high pressure center that is near 28N60W, and low pressure in Colombia/Panama, still is resulting in fresh to strong trade winds in the central Caribbean Sea, from Haiti and Jamaica southward. The comparatively fastest wind speeds are offshore NW Colombia. Similar wind speeds also are in the the northern Leeward Islands regional waters, especially to the N of Guadeloupe with sea heights there ranging from 7 feet to 8 feet. Moderate to fresh winds cover the rest of the area, except in the NW Caribbean Sea where mainly gentle to moderate winds prevail. The sea heights range from 8 feet to 11 feet to the E of the Lesser Antilles. The sea heights range from 8 feet to 10 feet in the central Caribbean Sea. The sea heights range from 6 feet to 8 feet in the remainder of the area that is from 18N southward from 82W eastward. The sea heights in the NW Caribbean Sea range from 3 feet to 5 feet. Precipitation: widely scattered moderate to isolated strong is from 13N southward from 72W westward, to the north of the E Pacific monsoon trough. Widely scattered to isolated passing rainshowers are in areas of low level moisture, that are embedded in the trade wind flow, in the remainder of the Caribbean Sea, to 60W. The gradient between high pressure to the northeast and lower pressure in South America will lead to fresh to strong winds in the Tropical Atlantic Ocean tonight, and waters offshore Colombia into Mon. Large N to NE swell will continue in the tropical N Atlantic through Mon night. Looking ahead, a cold front will move through the Yucatan Channel Tue night and may reach Honduras and Nicaragua Wed night. ...ATLANTIC OCEAN... A cold front passes through 31N80W, to Florida from 28N to 29N, into the south central Gulf of Mexico. Precipitation: widely scattered moderate to isolated strong is within 210 nm to the south and southeast of the cold front, and a second frontal boundary that is to the north of 31N between 70W and the SE U.S.A. Surface anticyclonic wind flow covers the Atlantic Ocean from 40W westward. A 1022 mb high pressure center is near 28N60W. A stationary front passes through 31N18W, to 24N31W. The southernmost point of a cold front reaches 31N26W. Precipitation: widely scattered moderate to isolated strong is from 27N northward between 16W and 42W. Fresh to strong winds, and sea heights in the range of 10 feet to 14 feet, are associated with the front. Fresh to strong winds are from the ITCZ to 14N between 20W and 30W. Fresh to locally strong trade winds are in the tropical Atlantic Ocean, due to the pressure gradient between the 1022 mb high pressure center and the ITCZ lower pressures. High pressure E of the area is leading to fresh winds near the Greater Antilles and gentle to moderate winds elsewhere. As the high moves east tonight, a cold front that has moved off the SE U.S. coast will move east across the northern waters early this week, leading to strong winds mainly N of 28N. Low pressure will form to the west of the area then move NE off the Florida coast by Tue night, bringing another potential for strong to near gale force winds near the low center over the NW waters Tue night through Thu. Large N swell impacting the Atlantic zones from 19N to 22N between 55W and 65W will diminish tonight. $$ mt/sk