000 AXNT20 KNHC 222346 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Dec 22 2020 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 2300 UTC. ...Special Features... Gulf of Mexico Gale Warning: A strong cold front will enter the NW Gulf Wed night followed by strong to gale force northerly winds and building seas. Strong gale-force winds are expected first near Tampico by early Thu morning, then near the Veracruz area early Thu afternoon. At that time, the front will extend from the Florida Big Bend to near 22N90W to the Bay of Campeche at 18.5N94W. On Thu, strong to gale force winds will dominate most of the Gulf waters in the wake of the front. Seas are forecast to build up to 12-13 ft. The front will exit the Gulf region Thu evening or night. Please read the latest NWS High Seas Forecast issued by the National Hurricane Center at website: https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from near the Sierra Leone/Liberia border to 07N14W. The ITCZ continues from 07N14W to 05N30W to the coast of northern Brazil near 02N51W. Scattered moderate convection is noted from 03N-07N between 10W-25W, from 03N-05N between 30N-34W, and from 03N-07N between 38W-42W. GULF OF MEXICO... High pressure centered over the SE CONUS dominates the Gulf of Mexico producing gentle to moderate NE-E winds over the eastern half of the basin, and E-SE winds over the western half. Cold air stratocumulus clouds are seen on visible satellite imagery mainly S of 26N while pockets of low level clouds are observed across the eastern slopes of the Sierra Madre Mountains in Mexico. The next cold front is forecast to enter the NW Gulf by Wed evening followed by strong to gale-force winds and building seas. A Gale Warning is already in effect. Please, see the Special Features Section for more details. CARIBBEAN SEA... The western Caribbean is under the influence of a ridge, anchored by a high pressure located over the SE CONUS. Patches of low level moisture, embedded in the trade wind flow, are noted moving westward across the basin. Isolated to scattered passing showers are possible with some of these clouds. Moderate to fresh easterly trades return across the basin with highest winds and seas across the southern Caribbean, near the coast of Colombia. Fresh to strong trade winds are expected near the coast of Colombia through Thu, with seas of 7-10 ft. The trade wind flow will weaken toward the end of the week as a strong cold front reaches the NW Caribbean. This front is expected to reach the Yucatan Channel and western Cuba by Thu night. Fresh to strong northerly winds will follow the front, forecast to reach from central Cuba to the Gulf of Honduras by Fri morning. Seas of 8-10 ft will build in the wake of the front, highest in the Yucatan Channel. There is a risk of heavy rain across northern Honduras on Saturday due to strong frontal incursion. ATLANTIC OCEAN... A cold front is over the western Atlantic and extends from 31N60W to the central Bahamas. Scattered showers are within 180 nm east of the cold front and north of 24N. A patch of low-level moisture, with isolated showers is located NE of the northern Leeward Islands. It is moving westward. A surface trough is analyzed there along 58W from 18N-23N. Farther E, another frontal boundary crosses between the Madeira Islands and the Azores, and continues SW to near 26N40W. Some shower activity is associated with this front. This boundary will dissipate within the next 24 hours. The pressure gradient between a 1036 mb high pressure located N of the area over the central Atlantic and lower pressures in the vicinity of the ITCZ supports fresh to locally strong trades N of the ITCZ to about 23N between 30W-50W based on satellite-derived wind data. In addition, another strong high pressure over the western Atlantic will bring a noticeable increase in winds and seas over the Atlantic waters W of 50W on Thu. A low pressure system is forecast to develop over the eastern Atlantic on Wed. This will bring an increase in winds and seas across the area. In addition, the pressure gradient between a strong high pressure of 1036 mb The western Atlantic cold front will continue to push east enhancing winds/seas. By the end of the week, a strong cold front will move off the northeast Florida coast with possible gale-force winds across the west Atlantic and seas of 10-12 ft. High pressure will build across the area in the wake of the front through the weekend. $$ GR