523 AXNT20 KNHC 192353 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Tue Jul 20 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 2300 UTC. ...TROPICAL WAVES... A tropical wave is likely along 22W/23W from 15N southward. The Hovmoller Diagram shows the westward propagation of the wave that should be added to the next surface analysis at 0000 UTC. The Tropical Wave Diagnostics and the TPW also support the presence of the wave. Scattered moderate to isolated strong convection is from 09N- 12N between 22W-26W. A tropical is across the tropical Atlantic along 42W from 20N southward and moving W near 10 kt. No significant convection is associated with this wave that is surrounding by African dust. A tropical wave is over the western Caribbean along 81W, and extends from the Cayman Islands southward across Panama, and moving W at 15 to 20 kt. Scattered to numerous showers and thunderstorms are ahead of the wave axis affecting parts of Honduras and Nicaragua. A tropical wave is over the Bay of Campeche along 93W/94W and extends southward into the eastern Pacific region. Scattered showers are noted near the northern end of the wave axis. ...MONSOON TROUGH/ITCZ... A monsoon trough enters the Atlantic Ocean through Senegal near 14N17W and extends to 11N30W to 07N44W. The ITCZ then continues from 07N44W to northern Guyana. Aside from convection related to the tropical waves, no significant convection is noted. ...GULF OF MEXICO... A tropical wave is over the Bay of Campeche. Please refer to the Tropical Wave section above for details. A ridge dominates the Gulf waters with a 1019 mb high pressure located over the NE Gulf. This system is producing mainly a light to gentle anticyclonic flow across the basin based on the most recent scatterometer data. Seas are generally 1-3 ft across the entire Gulf. The northern portion of a tropical wave currently located over the Caribbean Sea along 81W is analyzed as a trough over the NW Bahamas and central Cuba. This system is forecast to approach South Florida late tonight into Tuesday increasing the likelihood of showers and thunderstorms. For the forecast, as it is normal for this time of the year, the Bermuda-Azores High extends a ridge across Florida into the Gulf region. A high pressure cell sometimes develops over the NE Gulf. This system will continue to dominate the Gulf waters with gentle to moderate winds the rest of the work-week. The exception will be moderate to fresh NE-E winds to the west of the Yucatan Peninsula Wed night through Fri night due to local effects induced by a thermal trough. ...CARIBBEAN SEA... A tropical wave is over the western Caribbean. Please refer to the Tropical Wave section above for details. Showers and thunderstorms have flared up across most of Cuba and Hispaniola. An upper-level trough, that crosses the SE Bahamas and eastern Cuba into the NW Caribbean, combined with the northern extent of the aforementioned tropical wave is likely causing this convective activity. Fresh to strong trades are seen over the south-central Caribbean and near the tropical wave located along 81W. Moderate trades are noted over the eastern Caribbean with gentle to moderate winds over the NW part of the basin. Seas are in the 6-9 ft range over the south-central Caribbean, 4-6 ft over the eastern Caribbean, and 2-5 ft over the NW Caribbean. For the forecast, high pressure N of the Caribbean Sea combined with the Colombian low will support near gale force winds within about 90 nm of the coast of Colombia, and in the Gulf of Venezuela mainly during the overnight and early morning hours through at least Thu. In addition, expect an increase in areal coverage of the fresh to strong wind reaching as far north as Hispaniola adjacent waters. Fresh to locally strong easterly winds are expected in the Gulf of Honduras through Thu night. ...ATLANTIC OCEAN... A pair of tropical waves are between the west coast of Africa and the Lesser Antilles. Please refer to the Tropical Wave section above for details. The Bermuda-Azores High dominates the Atlantic forecast waters with a couple of centers, one of 1026 mb located E of Bermuda near 32N75W, and the second one near 31N36W. Mainly patches of low level clouds are seen over the ocean. Moderate to fresh NE winds are noted around the southern periphery of the ridge, and near the coast of Morocco and Mauritania. Seas are in the 5-7 ft range within these winds. For the forecast W of 65W, high pressure will be in control of the weather pattern across the region. Fresh to strong easterly winds will pulse in the late afternoon and evening hours just off north of Hispaniola, including the approach to the Windward passage for the next several days. $$ GR