000 AXNT20 KNHC 211048 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 UTC Sun May 21 2023 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 0600 UTC surface analysis and satellite imagery through 0930 UTC. ...SPECIAL FEATURES... Excessive Rainfall in Panama and Colombia: A deepening upper level trough across the western Atlantic is digging southward across eastern Cuba and Haiti and into the central Caribbean. This feature is interacting with broad low pressure in Colombia and Panama, and with the monsoon trough. Widespread convection along the monsoon trough across the eastern Tropical Pacific continues to flare across Costa Rica, Panama and Colombia this morning, S of 10N, and has developed across portions of Venezuela in recent hours. Upper level atmospheric conditions are expected to remain favorable for continued strong convection across these areas through Monday, then will shift eastward and become concentrated across Venezuela and the southeast Caribbean Monday through early Tuesday. Please, refer to the latest forecasts from your local national meteorological service for more information. Volcanic Ash from Popocatepetl: Two large eruptions from Popocatepetl Volcano in Mexico near 19N98.6W have been observed overnight, sending volcanic ash as high as 32000 ft into the atmosphere. Winds at middle and upper levels have transported the ash E-NE to the coast, and over nearshore waters of the Gulf of Mexico from 19N to 22N between 96W and the Mexican coast. This ash may be reaching the surface, and could restrict visibilities to 3 to 5 nm across this area. Ash may spread farther offshore to 95W later today. Mariners should exercise caution. If mariners encounter volcanic ash or floating volcanic debris...you are encouraged to report this observation to the National Hurricane Center by calling 305-229-4424. ...TROPICAL WAVES... An Atlantic tropical wave is along 29W from 11N southward, moving westward 10 knots. Scattered moderate isolated strong convection is noted from 01N to 07.5N between 29W and 34W. Strong upper level wind shear continues to weaken the convection associated with this wave. An Atlantic tropical wave is along 13W, from 14N southward, moving westward 5 to 10 knots. Scattered moderate convection dots the waters offshore of Africa, from 02N to 09N E of 18.5W to the coast of Africa. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coastal plains of Guinea near 10N14.5W to 04.5N22W. The ITCZ continues from 04.5N22W to 04N29W, then resumes from 04N32W to the coast of NE Brazil near 03N51W. Scattered moderate convection is noted from 01N to 04N between 00W and 16W. Scattered moderate to strong convection is noted from 04N to 06N between 48W and the coast. GULF OF MEXICO... See the special features section above for information on the ongoing volcanic ash spewing from Popocatepetl across the coastal waters of Mexico. A weak cold front has shifted SE into the Gulf overnight and extends from the central Louisiana coast to just south of Brownsville, Texas. An upper level trough across NE Mexico and southern Texas is supporting moderate convection aloft, that is producing light to moderate rain within 90 nm of the central Texas coast. A 1020 mb high pressure center is located ahead of the front near 27N94W. Light to gentle anticyclonic flow prevails across the basin SE of the front, while light NW to W winds trail the front. Seas are generally 3 ft or less. Weak high pressure will dominate the Gulf of Mexico through early next week, inducing light to gentle winds and slight seas. A diurnal trough will move offshore each night W of the Yucatan Peninsula, with moderate N to NE winds ahead of it. A weak frontal trough will sink into the northern Gulf Wed and move southward, and gradually produce gentle to moderate N to NE winds across the entire basin. CARIBBEAN SEA... Please, read the SPECIAL FEATURES section, for details about heavy rainfall Panama and Colombia during the next few days. Broad troffing prevails across the central Caribbean from Haiti southward, as an upper level trough digs southward across eastern Cuba and Haiti, and has carved a surface trough across the Atlantic along 72W. This pattern is producing gentle to moderate E to SE winds to the east of the trough, and gentle to moderate NE winds west of the trough, except fresh along the coast of NW Colombia. Seas are 4 to 5 ft E of the trough and 4 to 6 ft W of the trough. Winds are light and seas 3 ft or less across the NW basin. Very active convection continues across the waters S of 10N and inland across the lands of South America. A weakening pressure gradient across the basin will lead to gradually diminishing tradewinds and slight to moderate seas over the Caribbean E of 80W into the middle of next week, as an inverted surface trough N of the area along 72W develops into elongated low pressure and slowly lifts northward. Scattered showers and thunderstorms will impact waters near the coasts of Panama, Colombia and Venezuela through Mon morning then shift across the Caribbean waters E of 68W Mon through Tue. ATLANTIC OCEAN... A deep layered upper trough is across the western Atlantic along 71-74W and is digging southward across eastern Cuba and Haiti. A vigorous middle level cyclonic circulation has carved a surface trough along 72-73W, from Haiti northward to 27N. Very active convection continues near the surface trough and upper low, where scattered moderate to strong convection is noted from 20N to 29N between 65W and 72W. Moderate to fresh SE winds are found E of the trough across this area of convection, where seas are 6 to 7 ft. Gentle to locally moderate anticyclonic winds are elsewhere W of the trough, where seas are 3-5 ft. Farther E, the 1031 mb Azores high is centered near 41N33W and extends a ridge W-SW to 70W. Moderate to fresh ENE to ESE winds are found S of the ridge and 20N, where seas are 6 to 8 ft. Fresh N to NE winds are south of the high, N of 30N between 30W and the Azores, where seas are 7 to 9 ft. For the forecast W of 55W, the Atlantic high pressure ridge will generally remain in place through Tue. The surface trough along 72W is expected to develop into elongated low pressure late today and move slowly N-NE through Wed. Scattered showers and thunderstorms and freshening S to SE winds are expected near and E of the trough axis through Wed night. Another frontal trough may move off the SE US coast and impact far NW waters Thu. $$ Stripling