000 AXNT20 KNHC 102302 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Sun Jul 11 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 2230 UTC. ...TROPICAL WAVES... A tropical wave extends its axis along 36W, from 10N southward, is moving west at 15 to 20 kt. No convection is noted with this wave at this time. A tropical wave extends its axis along 60W, from 26N southward, is moving west at 20 to 25 kt. Scattered showers are noted over the southern portion of the wave from 10N to 17N between 52W and 60W. This tropical wave marks the leading edge of the Saharan Air Layer, which based on satellite data is north of 10N and extends east of the wave axis to Africa. A trade wind surge is anticipated tonight and tomorrow as the tropical wave reaches the Leeward Islands and the E Caribbean. A tropical wave extends its axis along 75W, from 13N southward, is moving west at 10 to 15 kt. Scattered moderate convection is inland over northern Colombia and reaching the adjacent Caribbean waters south of 13N between 70W and 80W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from Senegal and Guinea-Bissau near 12N17W to 04N25W. Segments of the ITCZ extend from 04N25W to 03N33W and from 03N39W to the coast of Brazil near 04N51W. Scattered showers are noted near the monsoon trough from 04N to 11N and east of 20W. GULF OF MEXICO... A 1021 mb high pressure is centered near 28N85W. With this, surface ridging extends across the basin. Light to gentle anticyclonic winds are noted in the E Gulf, with moderate to fresh SE winds in the W Gulf. Seas are 3-5 ft throughout the basin, except in the northwest and west-central Gulf where seas are 4-6 ft. For the forecast, the ridge will lift north of the area tonight through Mon. This will support gentle to moderate winds and slight to moderate seas persist through mid week. The exception will be fresh to occasionally strong winds off the northwest Yucatan Peninsula and eastern Bay of Campeche during overnight hours through mid week, related to the surface trough that forms during the late afternoon each day. CARIBBEAN SEA... Please see the section for information on the tropical wave moving across the basin and the next one approaching from the east. Fresh to strong trade winds and 8 to 11 ft seas are noted across the south central and SW Caribbean, driven by the pressure gradient between the subtropical high north of the area and lower pressure over Colombia and W Venezuela. In the SW Caribbean, scattered moderate to isolated strong convection is present south of 12N between the coast of Colombia and the coast of Nicaragua. This convection is likely enhanced by the East Pacific Monsoon Trough, which extends along 10N between 76W-83W. Moderate to fresh trades are noted elsewhere in the Caribbean. Seas are 6-8 ft off the NE coast of Honduras, and 4-6 ft prevail elsewhere. For the forecast, Strong Atlantic high pressure ridge will begin to drift northward tonight and Sun and allow strong to near gale force tradewinds across the south-central Caribbean to weaken through Mon. Strong trades in the Gulf of Honduras will diminish Sun, but fresh trades will pulse nightly through the middle of next week. A large tropical wave approaching the Lesser Antilles will bring a surge in wind and waves behind it as it moves across the E Carib tonight through late Sun, and across the central Carib Mon through Wed. ATLANTIC OCEAN... Please see the section above for information the tropical waves moving across the basin. The subtropical high centered north of the area continues to dominate the tropical Atlantic. Moderate to locally fresh winds veer anticyclonically along the southern half of the ridge; winds diminish to gentle speeds over the Bahamas and far W Atlantic. In the W Atlantic north of 22N east of 70W, seas are 3-6 ft. Elsewhere in the basin, seas are generally 5-8 ft. For the forecast west of 65W, the high pressure ridge will lift north through Mon and support moderate to fresh E winds south of the ridge axis, with winds pulsing to fresh to strong along the north coast of Hispaniola mainly during the evenings into mid week. A large tropical wave approaching the Lesser Antilles will bring a surge in wind and waves to the SE waters tonight through Mon, then through the southern Bahamas late Mon and Tue. $$ ERA