000 AXNT20 KNHC 202319 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Dec 20 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... Atlantic Gale Warning: A cold front moving across the Gulf of Mexico will reach the waters east of northern Florida by early Monday morning. Currently, the front extends SW from a 1013 mb low pressure located over the NE Gulf of Mexico near 30N86W to near Veracruz, Mexico. The low is forecast to strengthen as it moves northeastward into the western Atlantic. Fresh to strong winds are expected on either side of the front by early Mon morning. Then, winds ahead of the front will reach gale-force N of 28N and within about 90 nm E of the front by early Mon afternoon. Seas are expected to build up to 12-13 ft within the area of gale- force winds. The low pressure will move well north of the area later on Monday as the cold front progresses quickly eastward across the western Atlantic. By Monday night, winds will diminish below gale force ahead of the front expected to reach from near Bermuda to central Cuba at that moment. Please read the latest High Seas Forecast at https://www.nhc.gov/text/MIAHSFAT2.shtml for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the border of Sierra Leone and Guinea near 09N13W to 08N17W. The ITCZ continues from 08N17W to 05N30W to 05N42W to the coast of Brazil near 03N51W. Scattered moderate and isolated strong convection is noted from 04N-07N between 22W-27W, and from 03N-07N between 31W-39W. GULF OF MEXICO... As previously mentioned, a cold front extends SW from a 1013 mb low pressure located over the NE Gulf of Mexico near 30N86W to Veracruz, Mexico. The most recent ASCAT pass showed fresh to strong wind within about 120 nm in the southern semicircle of the low center as well as near Veracruz. Moderate to fresh winds follow the front elsewhere. Doppler Radar indicates a band of showers with embedded thunderstorms ahead of the front approaching central Florida. Cold air stratocumulus clouds are in the wake of the front but mainly E of 93W. Low level clouds are banked-up against the Sierra Madre Mountains in Mexico. The cold front will reach the SE waters of the Gulf region tonight, moving across South Florida and the Straits of Florida by Mon morning. As the front moves SE of the Gulf by early Mon afternoon, high pressure will be in control of the weather conditions across the area. As a result, winds and seas will continue to gradually diminish. The next cold front is forecast to enter the NW Gulf by Wed evening followed by strong to gale-force winds and building seas. Gales are expected first near Tampico by early Thu morning, then near the Veracruz area early Thu afternoon. The front is forecast to exit the Gulf on Thu night. CARIBBEAN SEA... Latest scatterometer data revealed fresh to strong trade winds over the south-central Caribbean and in the Gulf of Venezuela. Fresh northeast winds are present south of Hispaniola. These winds are the result of the pressure gradient between high pressure located over the western Atlantic and lower pressure associated with the Colombian/Panamaniam low. These winds will persist over the south-central Caribbean most of the forecast period. Patches of low level moisture, embedded in the trade wind flow, are noted moving westward across the basin mainly north of about 14N. Isolated to scattered passing showers are possible with some of these clouds. Northeast winds over the SE Bahamas are also advecting patches of low-level moisture with possible isolated showers into eastern Cuba. A cold front, now moving across the Gulf of Mexico, is forecast to reach the Yucatan Channel and western Cuba on Mon, then will extend from central Cuba to northern Belize by Mon night and gradually weaken from eastern Cuba to the Gulf of Honduras on Tue. Another and stronger cold front is expected to reach the Yucatan Channel and western Cuba by Thu night. Fresh to strong northerly winds will follow the front. ATLANTIC OCEAN... A cold front will produce strong to gale force winds across the western Atlantic on Mon. Please, see the Special Features section for more details. Fresh to strong southerly winds are already noted over the waters E of NE Florida ahead of the front. Farther east, a cold front enters the forecast area near 31N40W, then continues SW to near 26N53W where it becomes stationary. Pockets of low level moisture, with embedded showers, are noted behind the front, including the Bahamas. Mainly low-level clouds are also noted along the frontal boundary. Moderate to locally fresh winds are seen per scatterometer data in the wake of the front, forecast to gradually dissipate W of 50W on Mon. A ridge prevails over the east Atlantic, anchored by a 1027 mb high pressure located mid-way between the Madeira Islands and the Azores. Fresh trade winds are observed along the southern periphery of the ridge affecting the Cabo Verde Islands and regional waters. $$ GR