128 AXNT20 KNHC 291714 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 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 1200 UTC surface analysis and satellite imagery through 1730 UTC. ...TROPICAL WAVES... An Atlantic tropical wave is near 29W from 18N southward and moving west around 10 kt. Scattered moderate convection is evident from 05N-09N between 26W-33W. This weak wave is mainly identifiable via 700 mb trough diagnostics. Another Atlantic tropical wave is near 49W from 18N southward and moving west around 15 to 20 kt. No significant convection is noted currently in association with the wave. However, the wave is apparent as a trough in the surface winds. A Caribbean tropical wave is near 66W from 17N southward across Central Venezuela, and moving west at 5 to 10 kt. Divergent flow associated with an upper-level low that is located just northwest of Puerto Rico is supporting scattered moderate convection is seen from 11N- 17N between 62W-66W. The wave is mainly diagnosed from 850 and 700 mb rawindsondes in the Caribbean. Another Caribbean tropical wave is near 81W from 13N southward through W Panama into the Eastern Pacific Ocean, and moving west around 10 to 15 kt. Scattered moderate to isolated strong convection is occurring from 6N-9N between 78W-82W, including eastern Panama. This weak wave is mainly identifiable via 700 mb trough diagnostics. ...MONSOON TROUGH/ITCZ... A monsoon trough extends across the coast of Senegal at 14N17W to 07N38W. At this time, there is no coherent ITCZ west of the monsoon trough. In addition to the convection associated with the tropical wave near 29W, scattered moderate convection exists from 05N-14N east of 26W. ...GULF OF MEXICO... A surface trough is noted over the northwestern Gulf of Mexico, near the southeast Texas Coast. Scattered moderate convection is associated with this trough from 23N to 29N between 94W to 98W. Another trough extends from the Big Bend of Florida into the northeastern Gulf of Mexico to 30N88W. Scattered moderate convection exists with this second trough from the Florida coast to 87W from 26N to 30N. Another diurnal trough is seen in the SW Gulf from 21N93W to 19N94W. Isolated moderate convection exists south of 21N west of 92W. Elsewhere, surface ridging extends westward into the eastern Gulf of Mexico. Fresh SE winds are occurring over the SW Gulf, while tranquil conditions prevail elsewhere. Seas are 2-4 ft across the Gulf. For the forecast, the surface trough over the NE Gulf will continue drifting south today before dissipating tonight. The second trough across the NW Gulf waters should also dissipate tonight. The Atlantic high pressure ridge will drift westward and dominate the Gulf region during the upcoming weekend then reorganize over the E Gulf by early next week. ...CARIBBEAN SEA... A moderate north-south pressure gradient between ridging north of the Caribbean and lower pressure over N South America is contributing toward fresh to strong NE to E trades over the south-central Caribbean and just south of Hispaniola. Elsewhere, the trades are gentle to fresh. Seas are 6-8 ft in the central Caribbean, 4-6 ft in the E Caribbean, and 3-5 ft in the W Caribbean. Besides the convection associated with the tropical waves near 66W and 81W, no significant deep convection is observed. For the forecast, freshening tradewinds are expected across E and central portions of the Caribbean through tonight as the Atlantic ridge builds modestly across the W Atlantic. Fresh to strong trades will prevail across south central portions as well as the south central coast of Hispaniola through Sun night before the ridge begins to weaken. Strong winds to around 30 kt are expected at night near the coast of Colombia and in the Gulf of Venezuela Fri night through Mon night. ...ATLANTIC OCEAN... The Atlantic ridge extends west-southwest from the 1029 mb Azores High across central Atlantic to Florida. The ridge is sustaining light to gentle trades across all of the waters, except for fresh SE winds just north of Hispaniola. Seas are 6-7 ft south of 22N and 4-5 ft north of 22N. In addition to the convection mentioned in the Tropical Waves and Monsoon Trough/ITCZ sections, scattered moderate convection is noted north of 30N between 65W-75W in association with a sharp upper-level trough. For the forecast W of 65W, 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 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. Moderate to fresh S to SW winds are expected across the far NW waters Sun night through Mon night. $$ Nepaul/Landsea