000 AXNT20 KNHC 182300 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 UTC Thu May 19 2022 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 2210 UTC. ...SPECIAL FEATURES... Global models continue to suggest a Central American Gyre (CAG) will form across the southwest Caribbean and Central America by Fri, and then gradually shift west to northwest across Central America through early next week. CAGs tends to enhance the strength of SW monsoon flow, and lift the monsoon trough well north of its typical position. This will increase convergent surface winds and advect abundant moisture northward, triggering widespread strong convection over Central America. Expect heavy rainfall commencing across Panama and Costa Rica tonight through Thursday, then spreading to parts of Guatemala and Honduras. Extreme rainfall is possible across the Pacific coasts of these countries, and also over southern Honduras and NE Nicaragua. This will increase the potential for flash flooding and mud landslides, especially near valleys in mountainous terrain. Please refer to products issued by your local weather service for more information. ...TROPICAL WAVES... A Atlantic tropical wave is along 36W, south of 11N, moving west at 15 to 20 kt. Scattered moderate to strong convection is seen near the southern portion of the wave from 03N to 05.5N between 33W and 40W. A Caribbean tropical wave is along 80W, south of 16N, moving west-northwest near 10 kt. Enhanced by a mid-level trough to it's NW, scattered moderate to strong convection is evident over the SW Caribbean Sea from 11N to 15N between 78W and 83W. ...MONSOON TROUGH/ITCZ... A monsoon trough exits the African coast of Senegal near 15.5N16.5W and extends to 11N24W. Earlier convection occurring offshore of Africa has dissipated. An ITCZ extends from west of the Atlantic tropical wave near 02N38W to north of the Amazon River Delta area near 01.5N50W. Numerous moderate to isolated strong convection is noted from 00N to 05.0N between 40W and the Brazilian coast. The eastern end of the Pacific monsoon trough and an embedded 1012 mb low near 10.5N77.5W are aiding in forcing scattered moderate convection near the Panama and Colombia coasts and adjacent Caribbean waters. ...GULF OF MEXICO... A surface ridge reaches west-southwestward from a 1019 mb high over the north central Gulf to near 28N87W. Light to gentle winds with 1 to 3 ft seas are found near the high across the E Gulf. Gentle to moderate SE winds and seas at 2 to 3 ft are present over the SW Gulf, while moderate to fresh S winds and seas of 4 to 5 ft dominate the NW Gulf. For the forecast, the high will maintain moderate to fresh S to SE winds over the W Gulf through Sat, and light to gentle variable winds across the E Gulf through Thu afternoon. Then a broad area of low pressure is expected to develop along Central America Fri, tightening the pressure gradient between itself and the Bermuda High. This should allow moderate to fresh SE to S winds to spread eastward across the entire Gulf thru early next week. Also, fresh to strong E to SE winds are forecast to develop off the northern Yucatan peninsula Fri into Sun night. ...CARIBBEAN SEA... Please see the Special Features section for information on a potential heavy rainfall event. Scattered showers across central and eastern Cuba and the Cayman Islands earlier today have ended as the supporting surface trough has drifted NW across the Yucatan Channel. Refer to the Tropical Wave and Monsoon Trough/ITCZ sections for additional weather in the basin. Moderate to fresh easterly trades with 5 to 7 ft seas are found over the south-central basin, north of Colombia to 15N. Gentle to moderate easterly trades and seas at 4 to 5 ft are evident across the eastern, north-central and SW basin. Gentle to moderate trades and seas of 2 to 4 ft prevail for the NW basin. For the forecast, surface ridging over the western Atlantic will continue to support moderate to fresh trade winds across the eastern and central Caribbean through today, with fresh to strong winds pulsing off Venezuela and northwest Colombia. Winds and seas across the basin are expected to increase Thu night into the weekend as the ridge strengthens and broad low pressure forms along Central America. Strongest winds are expected to be over the northwest, including the Gulf of Honduras, and south-central Caribbean during this period. ...ATLANTIC OCEAN... A surface trough runs southward from 28N76W across the central Bahamas to eastern Cuba. Convergent S to SW winds east of the trough are combining with mid-level wind shear to trigger scattered moderate convection from 22N to 30N between 57W and the central/SE Bahamas. A dissipating stationary front runs southwestward from southwest of Madeira across 31N19W to 27N28W with a surface trough to its west near 28N32W. Scattered moderate convection is seen near these features north of 26N between 20W and 35W. Southwesterly upper- level winds are streaming widespread thick cirrus across the east-central Atlantic, including the Cabo Verde Islands. The Atlantic ridge stretches west-southwestward from a 1020 mb high near Madeira across 31N25W to the NW Bahamas. This feature is promoting light to gentle winds and 3 to 5 ft seas north of 20N between 35W and the Florida coast/Bahamas. Farther east, gentle to moderate with locally fresh NE to E trades and 5 to 8 ft seas in northerly swell is evident north of 25N between the African coast and 35W. Gentle to moderate NE to ESE trades and seas at 5 to 8 ft are noted from the Equator to 20N between 27W and the Lesser Antilles. Gentle to moderate SSW to WNW monsoonal winds and seas of 4 to 5 ft prevail for the remainder of the Atlantic Basin. For the forecast west of 55W, the Atlantic ridge across the area will weaken slightly this evening into Thu as the tail of a cold front drags eastward to the north of 30N. The ridge will restore on Thu and support mainly light to gentle variable winds across the region through Sun night, except for moderate to fresh winds north of Hispaniola and the Great Bahama Bank. $$ Stripling