000 AXNT20 KNHC 141828 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Thu Oct 14 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 1750 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A 1007 mb low pressure is located NE of the Bahamas near 25.5N 68W with a trough extending along it from 27N65W to the low to 22N67W. This low is expected to deepen as it moves east today and accelerates to the northeast by Fri. By Friday evening at 16/0000 UTC, when the low is near 30N 50.5W, southwesterly gale force winds are expected to develop south of the low. Gale force winds are expected Friday night over portions of the area from 26N-31N between 42W-52W, as the area of gale force winds moves east-northeastward. The gales will finally move N of the area by 1800 UTC on Saturday. Seas up to 14 ft are expected within the area of gales. Please read the latest High Seas Forecast issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...TROPICAL WAVES... An Atlantic tropical wave has its axis along 37W south of 17N, moving W at 15-20 kt. Scattered moderate and isolated strong convection is noted from 06N-10N between 33W-40W. Dry air is preventing any showers N of 10N. Another Atlantic tropical wave has its axis along 57/58W south of 17N, moving W at 15 kt. Isolated moderate convection is within 60 nm of the wave axis from 10N-12N. A central Caribbean tropical wave axis extends from central Hispaniola near 19N71W to eastern Colombia near 05N 71.5W. The tropical wave is moving W at 10-15 kt. Scattered showers and isolated tstorms are attributed to this tropical wave within 90 nm either side of its axis from 13N-16.5N. A western Caribbean tropical wave has its axis along 84W, south of 19N, extending to the east coast of Nicaragua and to Costa Rica. The tropical wave is moving W at about 10 kt. Isolated to scattered showers near the wave are confined to areas south of 13N, including over southeast Nicaragua and Costa Rica. ...MONSOON TROUGH/ITCZ... A monsoon trough extends from the border of Guinea and Guinea-Bissau near 11N15W to 07.5N 23.5W. The ITCZ extends from 07.5N 23.5W to 08N35W, then continues W of a tropical wave from 07N39W to 08N50W to 09N56W. Aside from the convection mentioned in the tropical waves section, scattered moderate and isolated strong convection is noted from 06N-11N between 24W-33W, and from 06N-11N between 40W-52W. GULF OF MEXICO... Weak surface ridging covers most of the Gulf of Mexico. The latest ASCAT data shows gentle to moderate E winds covering most of the basin, east of 93W, where seas are 2 to 4 ft. Relatively dry conditions cover this area. Fresh SE to SSE winds are over the far western Gulf of Mexico, west of 94W, confirmed by the latest ASCAT data and NOAA buoy 42020, which reads 19 kt SSE and seas of 6 ft about 60 nm SE of Corpus Christi, Texas. Seas are 4 to 6 ft in this area. Strong thunderstorms are noted along the coast of Texas between Freeport and Corpus Christi. These storms are the result of remnant moisture from East Pacific post-tropical Pamela, which dissipated, and then combined with a weakening frontal boundary/trough. These thunderstorms are expected to weaken by late afternoon today as they drift offshore, and mostly dissipate by this evening. The weak ridge in place today will persist through Fri. A cold front will enter the NW Gulf Fri night with strong northerly winds following it. The front will reach from south-central Florida to the western Bay of Campeche Sun morning with fresh N to NE winds across most of the Gulf. Gale-force winds are expected to develop off of Veracruz by Sun morning through afternoon. Winds will diminish across the basin on Mon. CARIBBEAN SEA... An upper-level low centered near the central and northwest Bahamas extends an upper-level trough SW to Guatemala. Upper-level divergence to the east of the upper-trough axis is enhancing isolated to scattered moderate thunderstorms from 16N-21N between 73W-82W, including waters near Haiti, Jamaica and the Cayman Islands. Farther south, scattered moderate showers are south of 14N between 74W-84W. Elsewhere, isolated tstorms are seen over NE Venezuela. The latest ASCAT data shows moderate SE winds in the eastern Caribbean, where seas are 3 to 5 ft. ASCAT shows gentle wind speeds in the western half of the basin, where seas are 1 to 3 ft. A vigorous upper level trough persists from the Bahamas to the NW Caribbean and will support active weather across the central Caribbean and extreme NE Caribbean through Fri. Northerly swell will subside across the regional Atlc and Caribbean passages today. Low pres NE of the southern Bahamas will drift E-NE through Thu then accelerate NE into the weekend. This will weaken the pressure gradient across the Caribbean basin leading to tranquil marine conditions. ATLANTIC OCEAN... A 1007 mb low pressure is located NE of the Bahamas near 25.5N 68W with a trough extending along it from 27N65W to the low to 22N67W. This low will develop gale force winds by Fri evening north of 26N and east of 52W. See the Special Features section above for details on the Gale Warning. Another related surface trough is located just to the east, extending from 27N61W to 20N65W. A recent ASCAT pass shows strong to near-gale force S to SW winds on the east side of the eastern surface trough, from 21N-27N between 61W-64W. The ASCAT pass also showed strong winds from 25N-27N between 64W-67W. Seas of 6 to 8 ft are likely occurring in these areas of strong winds. An upper-level low centered over the central and NW Bahamas is providing upper-level divergence to its east, which is enhancing showers and thunderstorms over the surface features. Scattered moderate and isolated strong convection is seen from 20N-30N between 54W-67W. Gentle to moderate N to NE winds cover the area west of 70W with 4 to 5 ft seas. A cold front extends from 31N36W to 27N41W to 27N45W. A stationary front continues from 27N45W to 31N60W. Scattered moderate showers and tstorms are along and within 180 nm SE of the cold front. Scattered moderate showers and isolated tstorms are on either side of the stationary front between 50W-63W. The ASCAT pass from early this morning showed strong to near-gale force SW winds within 180 nm E of the cold front, mainly north of 28N and east of 37W, where seas are likely 10 to 12 ft. A surface ridge axis extends from 1021 mb high pressure near 37N16W to 27N25W to 21N36W to 20N45W to 21N55W. Gentle anticyclonic winds are near the ridge axis. The Cumbre Vieja volcano, on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Significant volcanic ash is possible near the volcano. 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/ For the forecast W of 65W, low pres 1007 mb near 25.5N 68W will begin to drift E-NE today then accelerate E-NE and exit the area by Fri. This system will continue to produce very active weather and impact the regional waters through Fri. Northerly swell across the regional waters will subside today. A cold front will move southeastward across Florida by the end of the weekend, bringing fresh northerly winds off the Florida coast. $$ Hagen