000 AXNT20 KNHC 091720 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Dec 9 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 1200 UTC surface analysis and satellite imagery through 1700 UTC. ...SPECIAL FEATURES... East Atlantic Gale Warning: A strong high pressure of 1037 mb persists over the Azores. This system is producing a tight pressure gradient off the coast of Morocco, generating N-NE gales in the marine zone of Agadir and the northern part of Tarfaya. These conditions are forecast to continue through 10/0300 UTC. Expect seas of 10-14 ft within the area of gale force winds. Please read the latest High Seas Forecast issued by Meteo France at website http://weather.gmdss.org/II.html for more details. ...MONSOON TROUGH/ITCZ... The monsoon trough has retreated inland in Africa. The ITCZ extends from the coastal plains of Liberia near 07N10W to 06N30W to 02N49W off the coast of Brazil. Scattered moderate to isolated strong convection is noted from 03N-09N between 22W-44W. GULF OF MEXICO... A weak stationary front extends from central Florida to 27N89W. This system is not generating significant weather and has steadily weakened over the last 24 hours. Gentle to moderate SE flow is present across the western Gulf of Mexico with light to gentle winds across the remainder of the basin. Sea heights are 1-3 ft across the majority of the region. For the forecast, the stationary front will lift back north as a warm front tonight through Fri. A high pressure ridge extending from the Atlantic to the central Gulf will gradually shift eastward through Sat afternoon in response to a strong cold front that will move over the NW Gulf by early Saturday Moderate to fresh southerly return flow will set-up across the western and central Gulf beginning tonight and through Sat ahead of the strong cold front. Fresh to strong northerly winds and building seas are expected in the wake of the front through late Sat night. CARIBBEAN SEA... The gradient between the high pressure ridging from the subtropics and low pressure near Colombia and Panama is generating enhanced easterly trade wind flow through the basin. Recent scatterometer wind data shows a small region of near gale force NE winds off the coast of Colombia near 11.5N75.5W, generating up to 8 ft wind waves. This area is surrounded by a fresh to strong ENE breeze throughout the central Caribbean with 5-7 ft seas. Moderate to fresh trades dominate the E basin with 4-6 ft seas. Gentle to moderate trades prevail across the NW Caribbean with 3-5 ft seas. Expect isolated to scattered passing showers throughout the basin. For the forecast, the pressure gradient will continue to support fresh to strong trades over the south-central Caribbean and in the Gulf of Venezuela through Fri night. Moderate to fresh trades will prevail elsewhere. High pressure will strengthen over the western Atlantic by tonight, and fresh to locally strong northeast winds will develop in the Windward Passage, the lee of Cuba and south of Hispaniola through Mon night. ATLANTIC OCEAN... A cold front extends from 31N69W to 28N78W where it becomes stationary and extends to central Florida. Winds behind the front are moderate northeasterly. A pre-frontal surface trough is noted from 26N27W to 31N68W with scattered showers and thunderstorms within 60 nm of the feature. Ahead of the trough and N of 28N, winds are moderate to fresh from the S-SW. Gentle to moderate winds are noted elsewhere west of 65W generating 4-6 ft seas. In the central Atlantic between 65W and 40W, winds are moderate to fresh from the east with 6-9 ft seas, increasing eastward. In the eastern Atlantic, east of 40W, winds are mainly fresh to strong from the E-ENE due to the enhanced pressure gradient between a 1037 mb high near the Azores and lower pressure over Africa. Seas are 9-11 ft with localized gale force winds and up to 14 ft seas along the coast of Morocco as described in the special features above. For the forecast west of 65W, the cold front will become stationary from near 31N59W to 28N78W on Fri and dissipate over the weekend. High pressure will build across the region in the wake of the front, producing moderate to fresh NE to E winds S of 22N, and mainly gentle to moderate winds N of 22N through Sat night. Another cold front will move off the northeast Florida coast early on Sun, and reach from near 31N65W to South florida by Sun night. This front is forecast to dissipate over the southeastern waters on Mon. High pressure behind the front will likely bring fresh to strong northeast to east winds mainly across the waters south of 27N by Mon night. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Marine and aviation interests should monitor this ongoing situation by reading the Volcanic Ash Advisory issued by Meteo-France, at http://vaac.meteo.fr/volcanoes/la-palma/. The latest advisory states that low ash concentration is expected near and SW of the volcano. $$ FLYNN