000 AXNT20 KNHC 102129 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Thu Nov 11 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 1800 UTC surface analysis and satellite imagery through 2200 UTC. ...SPECIAL FEATURES... A storm-force non-tropical area of low pressure located several hundred miles east-northeast of Bermuda is producing a large area of showers that extend near and to the north of its center along an associated frontal boundary. Although the shower activity has increased near the center today, the system has not acquired sufficient characteristics to be classified as a subtropical cyclone. There remains only a brief period through tonight for this system to become a subtropical storm before it reaches much cooler waters Friday morning. By this weekend, the system is expected to be absorbed by a larger non-tropical low. This system has a medium chance of development in the next 48 hours. Additional information on this system can be found in the Tropical Weather Outlook issued by the National Hurricane Center at website - nhc.noaa.gov/gtwo.php?basin=atlc&fdays=2 and in High Seas Forecasts issued by the National Weather Service at website - ocean.weather.gov/shtml/NFDHSFAT1.php ....MONSOON TROUGH/ITCZ... A monsoon trough exits the coast near the Guinea-Bissau/Guinea border at 11N15W to 08N17W. The ITCZ then continues from 08N17W to 06N32W to 09N40W to 06N55W. Scattered moderate isolated strong convection is noted from 05N to 09N between 17W and 27W. Scattered moderate convection is noted from 05N to 08N between 48W and 55W. ...GULF OF MEXICO... A surface trough extends over the SW Gulf from 21N93W to the Bay of Campeche. High pressure prevails elsewhere. Gentle to moderate winds are noted over the far NW Gulf, with light to gentle winds elsewhere. Seas are in the 3-4 ft range over the far NW Gulf and 1-3 ft elsewhere. For the forecast, gentle to moderate return flow will prevail through tonight, locally fresh in the western Gulf of Mexico. A cold front will move into the northern Gulf coastal waters Thu, stalling Thu night into Fri. Reinforcing high pressure will push the front across the Gulf Fri night through Sat night, moving southeast of the basin early Sun. High pressure will build in the wake of the front, with winds in the southeast Gulf increasing to fresh to strong early next week. ...CARIBBEAN SEA... A dissipating frontal boundary extends from the Windward passage to near Honduras. Scattered moderate convection is noted over the NW Caribbean in association to this front. Moderate to fresh winds prevail over the south central Caribbean. Gentle to moderate winds prevail elsewhere. Seas are in the 5-7 ft range over the south central Caribbean and 3-5 ft elsewhere. For the forecast, the front will gradually dissipate through the end of the week. Moderate to fresh winds in the NW Caribbean will diminish to gentle by the end of the week. Moderate to fresh winds will prevail across the remainder of the basin, pulsing to fresh to strong in the south-central Caribbean tonight and again Thu night. A new cold front is forecast to move into the NW Caribbean by the end of the upcoming weekend. ...ATLANTIC OCEAN... A cold front extends from 31N52W to the Windward Passage. A pair of surface trough extend across the eastern Atlantic. One trough extends from 28N33W to 22N32W. The second trough extends from 30N23W to 23N24W. Shallow convection is noted in the vicinity of the troughs. High pressure prevails elsewhere. Fresh to strong winds are noted within 60 nm east of the front north of 30N, and within 300 nm west of the front north of 30N. Seas of 10 to 12 ft prevail over these waters. Light to gentle winds generally prevail over the remainder of the tropical and subtropical waters north of 20N. Gentle to moderate winds prevail south of 20N. Seas of 7-10 ft prevail north of 22N between 52W and 78W. Seas of 4-7 ft prevail elsewhere. For the forecast west of 65W, the cold front will continue moving southeast through Thu, stalling and dissipating along 22N by Fri. Large seas following the front will gradually decay through the end of the week. The western remnants of the front in the form of a trough will linger between 70W and 77W into the early part of the weekend, with weak low pressure possibly developing along it before moving north of the area late Sat. The next cold front will move off NE Florida by Fri night, then stall. Reinforcing high pressure will slowly push the front across the region during the weekend into early next week. 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 latest Volcanic Ash Advisory issued by Meteo-France at website https://vaac.meteo.fr/volcanoes/la-palma/ $$ AL