000 AXNT20 KNHC 290553 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Thu Jul 29 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 0530 UTC. ...TROPICAL WAVES... An Atlantic tropical wave is along 27W from 18N southward and moving W at 10 to 15 kt. Scattered moderate convection is evident from 05N to 09N between 22W and 34W. Another Atlantic tropical wave is near 48W from 19N southward and moving W at 20 to 25 kt. Strong subsidence at mid and upper levels associated with a high near 24N48W is hindering any significant convection from flaring up near this wave. A Carribbean tropical wave is S of the Virgin and St. Croix Islands near 17N and southward across N Venezuela, and moving W at 5 to 10 kt. Aided by divergent flow related to an upper-level low near Puerto Rico at 20N66W, scattered moderate convection is seen over the Windward Islands, and NE and central Venezuela. Another Caribbean tropical wave is near 78W from 13N southward through E Panama into the Pacific Ocean, and moving W near 10 kt. Scattered showers and isolated thunderstorms are occurring across Panama and adjacent waters. ...MONSOON TROUGH/ITCZ... A monsoon trough extends across the coast of Africa near the Mauritania-Senegal border at 17N16W to 08N28W to 05N40W. The ITCZ then continues from 05N40W to N of NE Brazil at 06N45W. Scattered to numerous moderate convection is flaring up near the monsoon trough from 05N to 16N between the African coast and 20W. Scattered showers are found up to 200 NM N of the ITCZ between 39W and 44W. ...GULF OF MEXICO... A surface trough is over the central Gulf near 24N93W, while an upper-level trough stretches eastward from the Texas-Mexico border across the Gulf to a low near the Keys at 24N82W. Interaction between these features is triggering scattered showers and a few thunderstorms over the W central Gulf. Otherwise, the W periphery of the Atlantic ridge is promoting light to gentle winds and seas of 1 to 2 ft across the entire Gulf. For the forecast, the surface trough drifting W across the NW Gulf will continue to trigger off-and-on scattered showers and isolated thunderstorms. The trough will remain over the NW Gulf on Thu while gradually weakening. In its wake, the Atlantic high pressure will begin to build westward into the Gulf waters on Thu, with a high pressure cell developing over the eastern Gulf. This high will move westward and dominate the Gulf region during the upcoming weekend. ...CARIBBEAN SEA... An upper-level trough extends WNW from a low near Puerto Rico at 20N66W through another low N of Cuba into the Gulf of Mexico. Divergent winds S of these features are coupling with convergent trade winds to produce scattered showers and thunderstorms over E Jamaica and W Haiti, and the NW Caribbean Basin. Refer to the Tropical Waves section above for information on additional convection. Tightening pressure gradient between the Atlantic ridge and the low over N Colombia is creating fresh to locally strong trades with seas at 6 to 8 ft over the S central Caribbean basin. Gentle to moderate trades and seas of 2 to 4 ft are present along the W basin. Mainly moderate trades and seas of 4 to 6 ft prevail for the rest of the basin. For the forecast, gentle to moderate trade winds are expected across the basin tonight. The exception will be moderate to locally fresh winds near the coast of Colombia, in the Gulf of Venezuela and Gulf of Honduras, and S coast of Hispaniola. Winds will begin to increase across the E and central Caribbean late tonight through Thu night, then persist through the weekend, as the Atlantic ridge builds westward. Strong winds are expected at night near the coast of Colombia and in the Gulf of Venezuela through Mon. ...ATLANTIC OCEAN... Refer to the Tropical Waves and Monsoon Trough/ITCZ sections above for convection across the Atlantic Basin. The Atlantic ridge extends WSW from the 1029 mb Azores High across W central Atlantic to Florida. These features are sustaining light to gentle winds and seas of 2 to 4 ft N of 22N between 48W and the Bahamas. Gentle to moderate with locally fresh trades are seen from 10N to 22N between 35W and the Lesser Antilles, and near the Canaries Islands N of 20N between the NW African coast and 48W. Light to gentle SE to SW winds and seas at 4 to 7 ft prevail across the remainder of the basin. For the forecast W of 45W, the Atlantic ridge, centered on the Azores high, will dominate the forecast waters through the period, while a surface trough will remain over or just off the coast of the SE of United States. Expect fresh to locally strong easterly winds late afternoon through the night just off the N coast of Hispaniola, including approaches to the Windward Passage, most of the forecast period. $$ Chan