000 AXNT20 KNHC 101013 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun Oct 10 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 0600 UTC surface analysis and satellite imagery through 1000 UTC. ...SPECIAL FEATURES... A large non-tropical low pressure area is nearly stationary N of the forecast region, and about 85 nm southeast of Morehead City, North Carolina. While recent satellite wind data indicates that the center has become better defined while producing an area of gale-force winds in its northern semicircle, the associated shower and thunderstorm activity near the center is minimal and has not become better organized. This system could still become a short-lived subtropical storm later today, but environmental conditions should become unfavorable for any further development on Monday. The low is forecast to move slowly northward and approach eastern North Carolina later today. Interests in that area should monitor the progress of this system. Regardless of development, intermittent periods of locally heavy rains and gusty winds will affect southeastern and eastern portions of North Carolina during the next day or two. There is still a medium chance of development for this low over the next 48 hours. For more details, please read the latest Tropical Weather Outlook at https://www.hurricanes.gov and Mariners can read the latest High Seas Forecast from the Ocean Prediction Center at https://ocean.weather.gov for more information. ...TROPICAL WAVES... An Atlantic tropical wave is along 48W from 18N southwestward, moving W near 15 kt. A cluster of moderate to strong convection is along the wave axis from 08N to 15N and between 46W and 49W. Fresh to locally strong E to SE winds are noted per satellite derived wind data is association with this wave that is forecast to approach the Lesser Antilles by Mon evening. Another tropical wave is over the eastern Caribbean along 62W extending from the northern Leeward Islands to eastern Venezuela. Scattered moderate to isolated strong convection is noted mainly on the E side of the wave axis. Fresh to strong winds and moderate to rough seas follow the wave forecast to reach the US/UK Virgin Islands and Puerto Rico later today, and Hispaniola on Mon. A third tropical wave extends from eastern Cuba to northern Colombia where is helping to induce scattered showers and thunderstorms. Similar convective activity is observed between eastern Cuba and Jamaica. The wave is moving W at 10 to 15 kt. ...MONSOON TROUGH/ITCZ... A monsoon trough turns southwestward at the coast of Mauritania near 17N16W to 10N26W. The ITCZ then continues from 10N26W to 11N46W. Scattered moderate to isolated strong convection is flaring up near the ITCZ from 07N to 10N between 33W and 38W. ...GULF OF MEXICO... The southern end of a surface trough extends across South Florida into the SE Gulf, generating some shower and thunderstorm activity. The remainder of the Gulf region is under the influence of a ridge that is producing mainly gentle to moderate winds. Seas are in the 1 to 3 ft range throughout. For the forecast, the aforementioned trough will remain nearly stationary over the Straits of Florida over the next couple of days. A ridge will continue to dominate the Gulf waters during the next several days. Moderate to fresh return flow will prevail across the western Gulf through the middle of the week due to the pressure gradient between the ridge and lower pressures over Texas and NE Mexico. ...CARIBBEAN SEA... A tropical wave will move across the eastern Caribbean today while another tropical wave will approach the Lesser Antilles late on Mon. Please, see the Tropical Waves section for more details. Otherwise, gentle to moderate trade winds prevail, with the exception of light to gentle winds over the NW and SW Caribbean. Seas are 3 to 5 ft across most of the waters S of 18N E of 83W, and 1 to 3 ft over the NW Caribbean. Seas of 8-9 ft are noted over the Atlantic waters in the wake of the tropical wave located over the eastern Caribbean. An upper-level trough extends across central Cuba to the Gulf of Honduras, and is generating scattered showers and thunderstorms. For the forecast, increasing shower and thunderstorm activity, gusty winds and moderate to rough seas are expected with the wave passage over Puerto Rico later today into tonight, and across Hispaniola on Mon. Otherwise, gentle to moderate trade winds will prevail, except light to gentle winds in the NW Caribbean. ...ATLANTIC OCEAN... A large non-tropical low pressure area is nearly stationary N of the forecast region, and about 85 nm southeast of Morehead City, North Carolina. Please, see the Special Features section for more details. A surface trough extends from the low center across South Florida. This trough currently supports scattered showers and thunderstorms across the waters just E of the Florida peninsula. A large area of showers and thunderstorms covers the waters from 20N to 27N between 70W and 76W. A diffluent pattern aloft is helping to induce this convective activity. Another area of scattered showers with embedded thunderstorms is noted from 25N to 29N between 60W and 68W and is associated with a surface trough that extends from 28N53W to 27N69W. The remainder of the Atlantic forecast waters is under the influence of a ridge anchored on a 1034 mb high pressure located well NE of the Azores. The pressure gradient between the ridge and lower pressures over W Africa is resulting in an area of moderate to fresh N to NE winds near the coasts of Morocco and Western Sahara. A belt of moderate to fresh trade winds is also noted N of the Cabo Verde Islands, roughly from 17N to 24N and E of 28W to the coast of W Africa. A northerly swell event will begin to propagate across the central Atlantic waters by this evening, building seas to 8 to 11 ft N of a line from 31N36W to 27N50W to 31N62W by Mon morning. This swell event will cover most of the waters N of 24N E of 60W by Mon evening. The Cumbre Vieja volcano, that is on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Currently, volcanic ash is seen over the vicinity of the volcano. Marine and aviation interests should monitor this on-going situation, by reading the Volcanic Ash Advisory, that is issued by Meteo-France, at http://vaac.meteo.fr/volcanoes/la-palma/. $$ GR