509 AXNT20 KNHC 141031 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 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 0600 UTC surface analysis and satellite imagery through 1010 UTC. ...SPECIAL FEATURES... Atlantic Gale Warning: A 1009 mb low is located NE of the Bahamas near 24N70W with a trough extending along it from 28N65W to 21N70W. Scattered moderate convection is occurring along and east of this system from 20N to 28N between 65W and 71W. This low is expected to slowly drift east today and accelerate to the northeast by Fri. By late Fri night, southwesterly gale force winds are expected to develop south of the low, from 26N to 28N between 47W and 48W with seas building to 14 ft. As the low continues to move farther to the northeast outside of the forecast waters, the gale force winds will end by Sat morning. However, strong to near gale- force winds are expected to persist through Sat night. Please read the latest High Seas Forecast issued by the National Hurricane Center at website http://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for more details. ...TROPICAL WAVES... An Atlantic tropical wave has its axis along 35W, south of 17N and it is moving W at 10-15 kt. A few showers are noted near the wave axis from 03N and 08N. Dry air is suppressing the storm activity N of 10N. Another Atlantic tropical wave has its axis along 55W, south of 17N and it is moving W at 10-15 kt. A few showers are observed near the wave axis. However, dry air is suppressing the storm activity N of 11N. A Caribbean tropical wave has its axis along 70W, south of 19N, extending from the Dominican Republic to W Venezuela and E Colombia. The tropical wave is moving W at 10-15 kt. A few showers are seen near the wave axis. A second Caribbean tropical wave has its axis along 83W, south of 20N and it is moving W at about 10 kt. No deep convection is noted in association with the wave as it moves into a dry airmass. ...MONSOON TROUGH/ITCZ... A monsoon trough extends from the coast of Guinea near 10N14W to 07N23W. The ITCZ continues from 07N23W to 07N34W, then continues W of a tropical wave near 07N36W to the coast of French Guiana near 05N52W. Scattered moderate convection is noted near the monsoon trough and ITCZ from 02N to 10N between 14W and 31W. Scattered moderate convection is also noted near the ITCZ from 02N to 09N bteween 34W and 47W. ...GULF OF MEXICO... A 1018 mb high pressure system centered over the Mid-Atlantic extends to the Gulf of Mexico. A surface trough is found near the western coast of Florida and another one extends along 85W/86W from 15N-25N. Only a few shallow showers are seen in association with these troughs. The rest of the Gulf enjoys fairly tranquil weather conditions. The pressure gradient between the weak ridge and lower pressures across the southern United States and the remnants of Pamela over N Mexico results in fresh to strong SE winds W of 95W as shown in an overnight scatterometer satellite pass and surface observations. Seas of 4-6 ft are noted W of 94W, with the highest seas occurring off the S Texas and NE Tamaulipas coasts. Moderate or weaker winds and seas of 2-4 ft prevail 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 through Thu. Gentle to moderate breezes will persist elsewhere through Fri. A cold front enter the NW Gulf Fri night with fresh to strong northerly winds following it. The front will reach central Florida to western Bay of Campeche Sun morning with moderate to fresh N to NE winds across most of the Gulf. Gale- force winds could develop off of Veracruz by Sun morning and continue through the afternoon. ...CARIBBEAN SEA... A sharp upper level trough and upper level low is located in the NW Bahamas. This is enhancing the development of showers and thunderstorms to the east of a surface trough that extends from the NE Caribbean to well north of the Leeward Islands. The large area of convection is mainly N of 15N between 62W and 67W. These storms are impacting parts of Puerto Rico and the Virgin Islands. Overnight scatterometer data indicate that fresh to strong southerly winds are occurring in association with the strongest convection. Moderate or weaker winds prevail in the rest of the basin. The exception are locally fresh trades noted in between Cuba and Jamaica and within 60 nm of the central coast of Cuba. Seas of 3-5 ft are found E of 77W. Seas of 1-3 ft are prevalent elsewhere in the Caribbean. For the forecast, a vigorous upper level trough from the Bahamas to the NW Caribbean 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 tonight 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... See the Special Features section on the 1009 mb low NE of the Bahamas that will bring gale force winds to the central Atlc. The previously mentioned upper level low in the NW Bahamas continues to interact with a couple of surface troughs further to the east, producing a large area of showers and thunderstorms.The first trough is explained in the Special Features section. The other surface trough extends from 26N61W to 18N66W. Scattered moderate to isolated strong convection is found from the NE Caribbean to 29N and between 59W and 64W. Overnight scatterometer satellite data indicate that fresh to strong southerly winds are found with the strongest convection. Otherwise, light to gentle winds prevail in this area. The other feature of interest is a cold front that extends from a 996 mb low pressure system north of our area, entering the tropical Atlantic near 31N38W and continues SW to 27N49W. The front stalls from that point to near 31N59W. Scattered moderate convection is noted from 24N to 31N between 33W and 48W. Overnight satellite- derived wind data depict a large area fresh and strong cyclonic winds N of 24N and between 31W and 48W. The rest of the tropical Atlantic is dominated by a weak ridge centered near the Madeira islands, permitting fairly tranquil weather conditions and moderate or weaker winds. A widespread northerly swell continues to impact the north- central tropical Atlantic with seas of 8-12 ft, mainly N of 25N and between 33W and 55W. Seas of 4-7 ft are found W of 60W, while seas of 6-9 ft are noted S of 25N and W of 30W. Finally, seas of 5-8 ft are present E of 30W. 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, high pressure extending across the area will shift slowly E and weaken through the end of the week. Developing low pres 1009 mb near 24N70W 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 southward across Florida by the end of the weekend, bringing fresh northerly winds off the Florida coast. $$ AReinhart