000 AXNT20 KNHC 211750 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Mon Dec 21 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: As of 21/1500 UTC, a cold front extends from 32N74W to Miami, FL. According to a recent ASCAT pass, gale force SW winds are currently within 60 nm east of the cold front, to the north of 28.5N. Gale force winds will continue in advance of the front through early evening as the front moves quickly eastward. Seas as high as 12 ft are expected within the area of gale force winds. 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 coast of Sierra Leone near 08N13W to 07N15W, where it transitions to the ITCZ to 05N30W to the coast of Brazil near 04N51W. Scattered moderate and isolated strong convection is within 180 nm on either side of the axes between the coast of Africa and 42W. GULF OF MEXICO... As of 21/1500 UTC, a cold front extends from Key West to the Yucatan Channel to the western Yucatan Peninsula near 20N90W. This front transitions to a stationary front from 20N90W to 18N93W. Isolated showers are along and within 30 nm of the front over the Florida Straits and Yucatan Channel. High pressure is spreading over the Gulf behind the front with a 1022 mb high centered near Galveston, TX. A weak surface trough located near the coast of Mexico is producing isolated showers from Veracruz to Tampico. Moderate to fresh northwest winds will prevail over the far southeastern Gulf of Mexico as the cold front exits the basin today. The high pressure over the NW Gulf will drift east, allowing for southerly flow to return to most of the basin on Wed. A strong cold front will enter the NW Gulf on Wed night, and move quickly southeastward, exiting the basin Thu night or early Fri. Gale force winds are possible behind the front in the SW Gulf on Thu. CARIBBEAN SEA... As of 21/1500 UTC a cold front is moving southeastward through the Yucatan Channel. Isolated showers are near the front. Scattered moderate convection is seen in the Gulf of Honduras south of 18N and west of 85W. The remainder of the basin is relatively dry due to subsidence from mid-level ridging. The latest ASCAT pass shows fresh trade winds across the eastern and central Caribbean. Strong trade winds are seen off the coast of Colombia. The cold front currently over the Yucatan Channel will move southeastward over the NW Caribbean through tonight enhancing fresh to strong northerly winds though the Yucatan Channel. The front will weaken into Tue with easterly trades returning across the NW Caribbean. Highest winds and seas will continue to be in the southern Caribbean, near the coast of Colombia, pulsing to strong at nighttime through the forecast period. A strong cold front will slide southward past the Yucatan Channel into the NW Caribbean on Thu night. Strong N winds and building seas are likely Fri over the NW Caribbean behind the front. ATLANTIC OCEAN... As of 21/1500 UTC, a cold front extends from 32N74W to Miami, FL. Scattered moderate convection is seen within 90 nm E of the front, north of 28N. Gale force SW winds are occurring ahead of the front. Please see the Special Features section above for more details on the Gale Warning. Strong NW winds are seen behind the front, north of 27N. Farther east, a cold front extends from 32N33W to 28N42W, where it becomes stationary to 24N59W. Isolated showers are within 120 nm north of the stationary front and also ahead of the cold front. A surface trough extends from 24N46W to 18N48W with scattered showers. A 1028 mb high near 34N54W is spreading ridging between Bermuda and the stationary front with mostly moderate wind speeds. Surface ridging dominates the northeast Atlantic with a 1029 mb high centered near 35N13N and a 1026 mb high near 28N34W. As for the forecast: The west Atlantic cold front will reach from 31N64W to eastern Cuba by early Tue, and continue moving eastward on Wed. Gale force winds will continue east of the front, north of 29N, through early this evening, with fresh to strong winds behind the front. These winds will diminish tonight. By Thu night, a strong cold front will push off the east coast of Florida. This front will bring strong winds and enhanced seas to the waters north and east of the Bahamas, along with showers and thunderstorms. $$ Mora/Hagen