000 AXNT20 KNHC 181756 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Wed May 18 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 1200 UTC surface analysis and satellite imagery through 1630 UTC. ...SPECIAL FEATURES... Global models continue to suggest a Central American Gyre (CAG) forming near the western Caribbean by Fri, and then gradually shifting westward across Central America through early next week. CAG tends to enhance 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 from the southern parts of Guatemala and Honduras, southward to Panama. Extreme rainfall is possible near the Pacific coast of these countries, and also over southern Honduras and NE Nicaragua. This will increase the potential for flooding, 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 near 10N33W and southward, moving west at 15 to 20 kt. Scattered moderate convection is seen near the southern portion of the wave from 02N to 05N between 33W and 37W. A Caribbean tropical wave is southwest of Jamaica near 17N78W and southward, moving west-northwest near 10 kt. Enhanced by a mid- level trough in the vicinity, scattered moderate to isolated strong convection is evident over the SW Caribbean Sea from 10N to 14N between 77W and 82W. ...MONSOON TROUGH/ITCZ... A monsoon trough exits the African coast near the Mauritania- Senegal border to south of the Cabo Verde Islands at 13N23W. Scattered moderate to isolated strong convection is found south of the trough near and off the Guinea-Sierra Leone-Liberia coast from 05N to 10N between 11W and 19W. An ITCZ extends from 01N37W to north of the Amazon River Delta area near 02N50W. Numerous moderate to isolated strong convection is noted from 01N to 05N between 82W and the Brazilian coast. The eastern end of the Pacific monsoon trough and an embedded 1010 mb low near 10N81W are producing scattered moderate convection near the Costa Rica-Panama-Colombia coast and adjacent Caribbean waters. ...GULF OF MEXICO... A surface ridge reaches west-southwestward from a 1018 mb high over the NW Gulf to near Tampico, Mexico. 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 3 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 near Fri, tightening 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. Convergent trades in the wake of a surface trough over western Cuba and west of the Cayman Islands are causing scattered showers across central and eastern Cuba and the Cayman Islands. Refer to the Tropical Wave and Monsoon Trough/ITCZ sections for additional weather in the basin. Moderate to fresh easterly trades with 6 to 7 ft seas are found over the south-central basin, just north of Colombia. 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 expected to be over the northwest and south-central Caribbean during this period. ...ATLANTIC OCEAN... A surface trough runs southward from 28N73W across the central Bahamas to near the Windward Passage. Convergent southerly winds east of the trough are combining with mid-level wind shear to trigger scattered moderate convection from 22N to 30N between 59W 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 1022 mb high near Madeira across 31N24W 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 slightly weaken today into Thu as the tail of a cold front moves 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. $$ Chan