000 AXNT20 KNHC 082202 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sat Oct 9 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 low pressure system located a couple of hundred miles east of the coast of South Carolina is gradually becoming better defined. Although the associated shower and thunderstorm activity is currently disorganized, environmental conditions could briefly become marginally conducive for the low to acquire subtropical characteristics by Saturday night and early Sunday. By early next week, the low is expected to interact with a frontal boundary, which should end the opportunity for any subtropical or tropical formation. The low is forecast to meander offshore the Carolinas today, and then slowly move back toward the west-northwest and northwest on Saturday, bringing the system closer to the coast of North Carolina. Interests along the coast of North and South Carolina should monitor the progress of this system. Regardless of development, intermittent periods of locally heavy rains and gusty winds will affect eastern portions of the Carolinas through the weekend. The disturbance has a medium chance of development over the next 48 hours. Please read the latest Tropical Weather Outlook at https://www.hurricanes.gov and the High Seas Forecast from the Ocean Prediction Center at https://ocean.weather.gov for more information. ...TROPICAL WAVES... The axis of a tropical wave is near 40W south of 16N, moving W at 15 to 20 kt. Deep convection near the southern portion of this wave is mainly associated with the nearby ITCZ. The northern portion is devoid of deep convection due to dry Saharan air. The axis of a tropical wave is near 68W south of 19N, moving W at 15 to 20 kt. Scattered moderate convection is noted from 12N to 16N and between 64W and 70W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from 12N16W to 09N18W. The ITCZ continues from 09N18W to 08N30W. It resumes from 07N41W to 04N51W. Scattered moderate convection is noted from 04N to 11N between 18W and 32W, and from 02N to 09N between 41W and 49W. ...GULF OF MEXICO... A cold front extends from northern Florida to the central Gulf. A pre- frontal trough extends from central Florida to near 26N84W. Scattered moderate and isolated strong convection is noted within 240 nm SE of the front. A surface trough extends from 22N90W to the Bay of Campeche. Scattered moderate convection is within 90 nm of the trough axis. High pressure prevails elsewhere over the NW Gulf. Gentle to moderate winds prevail over the northern Gulf west of the cold front. Light to gentle winds are noted elsewhere. Seas are in the 3-4 ft range over the SW Gulf, and 1-3 ft elsewhere. For the forecast, the pressure gradient between high pressure over the western half of the Gulf and the trough in the Bay of Campeche supports moderate to fresh northerly winds over the Veracruz adjacent waters. These winds are forecast to diminish this evening. Weak high pressure will build across the basin this weekend into early next week, and support moderate to locally fresh return flow W of 90W Sun through Wed night. ...CARIBBEAN SEA... A weak pressure gradient prevails over the Caribbean. Moderate to fresh winds prevail over the south central Caribbean with gentle to moderate winds over the eastern Caribbean as well as the north central Caribbean. Light to gentle winds are over the western Caribbean. Seas are in the 6-7 ft range over the south central Caribbean, and 3-5 ft elsewhere. For the forecast, moderate to locally fresh trades are expected mainly across the eastern half of the Caribbean through Tue. ...ATLANTIC OCEAN... Low pressure is centered north of the area. An associated surface trough extends from the low SW to central Florida. Scattered moderate and isolated strong convection is noted west of the trough as well as within 90 nm east of the trough. Another surface trough extends from 28N61W to 20N69W. Scattered moderate convection is noted within 120 nm of the trough axis north of 22N. Another trough extends from 30N52W to 28N48W. Scattered moderate convection is noted within 180 nm of the trough axis. A third trough extends from 16N52W to 09N58W. Scattered moderate and isolated strong convection is noted within 120 nm of the trough axis. Moderate to fresh winds prevail over the deep tropics south of 20N with seas in the 6-8 ft range. Light to gentle winds generally prevail over the tropical and subtropical waters north of 20N. Seas are in the 5-7 ft range east of 55W in northerly swell, and in the 3-5 ft range over the open waters west of 55W. West of the Bahamas, seas are in the 1-3 ft range. The Cumbre Vieja volcano, that is on the island of La Palma in the Canary Islands, has been erupting since 19 September at 1410 UTC. An ash plume is partially identifiable on satellite imagery drifting westward toward the Tenerife Island. Top is estimated with Webcams at 11,000 ft. 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/. For the forecast W of 65W, the low pressure system located a couple of hundred nm east of the coast of South Carolina continue to support scattered showers and tstms across the offshore waters N of the Bahamas. The low will continue to support active weather over the northern offshore waters tonight, with this activity extending across the Bahamas during the remaining weekend. $$ AL