000 AXNT20 KNHC 130427 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 UTC Wed Oct 13 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 0000 UTC surface analysis and satellite imagery through 0420 UTC. ...TROPICAL WAVES... An Atlantic tropical wave has its axis along 27W, south of 18N and it is moving W at 10-15 kt. Scattered moderate to isolated strong convection is observed from 08N to 14N and between 20W and 30W. Another Atlantic tropical wave has its axis along 49W, south of 19N and it is moving W at 15 kt. Scattered moderate to isolated strong convection is noted where the wave interacts with the ITCZ from 05N to 11N and between 44W and 55W. The northern portion of the wave is surrounded by dry Saharan air and subsident northerly flow aloft, suppressing the development of showers and thunderstorms. A Caribbean tropical wave has its axis along 63W, south of 20N, extends from the Leeward Islands to E Venezuela, and it is moving W at 10-15 kt. Scattered moderate to isolated strong convection is seen on satellite imagery from 10N to 20N and between 56W to 65W. A recent scatterometer satellite pass show fresh to strong SE-S winds within 170 nm to the E of the wave axis, mainly from 15N and 20N. A second Caribbean tropical wave has its axis along 79W, south of 20N and it is moving W at 10-15 kts. No deep convection is noted in association with the wave as it moves across very dry airmass. ...MONSOON TROUGH/ITCZ... A monsoon trough extends from the coast of Senegal near 12N16W to 09N25W and to 07N31W. A segment of the ITCZ continues from 07N10W to 06N40W and to 06N47W, with another segment reaching from 06N50W to the coast of Suriname near 06N55W. Scattered moderate to isolated strong convection is present near the monsoon trough axis E of 20W. ...GULF OF MEXICO... A weak ridge over the eastern United States extends to the Gulf of Mexico and maintains tranquil weather conditions across the basin. The pressure gradient between the ridge and lower pressures across the southern United States and northern Mexico results in fresh SE winds across the western Gulf waters, especially W of 94W. Seas in this region are 3-5 ft. Fresh NE-N winds are also present near the NW coast of the Yucatan peninsula. Moderate or weaker anticyclonic winds with seas of 1-3 ft are prevalent elsewhere in the Gulf. For the forecast, high pres extends weakly from the eastern U.S. southwestward to the N central Gulf and will influence the Gulf waters during the next several days. Moderate to fresh southerly winds are expected over the western Gulf between the ridge and lower pressure over the Southern Plains and northern Mexico tonight through late Thu. Gentle to moderate breezes will persist elsewhere through Fri. A cold front enter the NW Gulf Fri night and reach central Florida to western Bay of Campeche Sun morning. ...CARIBBEAN SEA... An upper level trough off the SE United States extends to the NW Caribbean Sea allowing for scattered showers and isolated thunderstorms from the coast of Colombia to Hispaniola, between 70W and 70W. A surface trough extends from southern Florida to the Gulf of Honduras and a few shallow showers are seen near the trough axis. The rest of the basin remains fairly quiet outside of the tropical wave in the E Caribbean previously described in the Tropical Waves section. Fresh trades are noted within 150 nm of the coast of NE Venezuela, including the waters surrounding the ABC islands. Moderate or weaker trades prevail elsewhere. Seas of 3-5 ft are occurring in the E, central and SW Caribbean, while 1-3 ft are present elsewhere. For the forecast, a tropical wave along 64W will move westward through tonight, and spread fresh winds and very active weather across the extreme NE Caribbean and adjacent Atlc waters. Northerly swell will build across the regional Atlc and move through the Caribbean passages through late Wed. Active weather associated with an upper level trough along 59W will continue through Wed morning. Low pres is expected to develop E of the southern Bahamas on Thu and drift eastward into the weekend. This will weaken the pressure gradient across the Caribbean basin leading to tranquil marine conditions. ...ATLANTIC OCEAN... Recent scatterometer satellite data depict a well-defined surface trough extending from near the northern coast of Haiti to 28N71W. This feature is interacting with an upper level trough located to the west, producing a large area of scattered showers and isolated thunderstorms, mainly from 20N to 31N and between 62W and 75W. Satellite-derived wind data indicate fresh to strong cyclonic winds within 100 nm of the coast of Hispaniola. The other feature of interest in the tropical Atlantic is a 1004 mb low pressure located just north of our area, but a surface trough extends south to 24N46W. Scattered moderate convection is observed on satellite imagery within 170 nm of the trough axis. Scatterometer satellite data indicate fresh to strong cyclonic winds N of 28N and between 44W and 55W. Fairly tranquil weather conditions and moderate or weaker winds prevail elsewhere in the basin. Widespread northerly swell continues impact the region, reaching 8-11 ft mainly north of 15N between 30W and 65W. Seas of 5-8 ft are found elsewhere. The Cumbre Vieja volcano, that is on the island of La Palma in the Canary Islands, has been erupting since 19 September 2021. Currently, significant volcanic ash is seen in the vicinity of the volcano drifting southward closer to the surface. Marine and aviation interests should monitor this ongoing situation, by reading the Volcanic Ash Advisory, that is issued by Meteo-France, at http://vaac.meteo.fr/volcanoes/la-palma/. For the forecast west of 65W, high pressure centered over the central Atlantic will shift slowly E and weaken through the end of the week. A low level trough extends from the southern Bahamas to 28N71W. Very active weather is expected with this trough through Wed as it drifts eastward. Low pres may form along the trough by Thu as it shifts E of 60W. Northerly swell across the regional waters will peak tonight E of 70W then begin to fade Wed. $$ DELGADO