000 AXNT20 KNHC 180359 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0400 UTC. ...SPECIAL FEATURES... Global models suggest that a Central American Gyre event will impact the western Caribbean and shift across Central America late this week into the weekend. Climatologically, this is the favored time of year for these broad low pressure areas to develop. CAG's increase SW monsoon flow, and lift the monsoon trough well north of its typical position, which advects abundant moisture northward. This CAG will bring an increase in convection, starting over southern portions of Central America, before gradually moving north. Expect locally heavy rainfall over portions of Central America, especially in mountainous terrain. Please refer to products issued by your local weather service for more information. ...TROPICAL WAVES... A tropical wave is analyzed with axis along 30W and south of 11N, moving west at 15 kt. Recent scatterometer data revealed a weak surface signature and convection has decreased over the last 24 hours. Scattered weak convection is noted from 01N-16N between 23W-39W. A tropical wave is located in the central Caribbean with axis along 77W and south of 17N, moving west-northwest at 15-20 kt. This position corresponds with an area of enhanced moisture seen on total precipitable water imagery. Scattered moderate convection is noted south of 17N between 72W-82W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Senegal near 16N17W to 10N25W. The ITCZ is analyzed west of a tropical wave from 01N34W to the mouth of the Amazon River near the equator and 50W. Scattered moderate with isolated strong convection is noted south of 02N between 40W-47W. GULF OF MEXICO... High pressure in the central Gulf is suppressing convection over the basin. In the eastern Gulf, winds are gentle with 1-2 ft seas. In the western Gulf, southeasterly winds are moderate with 2-4 ft seas. Buoys and oil platforms are reporting patchy haze in the central Gulf due to ongoing agricultural fires in Mexico and northern Central America. For the forecast, high pressure over the central Gulf will maintain gentle to moderate S to SE winds over the western half of the basin and light to gentle variable wind across the eastern Gulf into mid week. Moderate to fresh SE winds will persist over the western Gulf tonight into Sat night, expanding to the eastern Gulf Thu night through Sun as low pressure develops along Central America and the Bermuda high extends into portions of the E Gulf. Meanwhile expect NE winds pulsing to fresh or occasionally strong off the western Yucatan peninsula mainly at night through the week. CARIBBEAN SEA... Please see the Special Features section for information on a potential heavy rainfall event. The gradient between high pressure in the Atlantic and lower pressure over South America is maintaining moderate to fresh easterlies in the eastern Caribbean with gentle to moderate winds in the central Caribbean. Light to gentle winds are west of a surface trough along 82W/83W. Seas are 4-6 ft across the basin, except 2-4 in the NW Caribbean. Scattered showers and isolated thunderstorms are observed in the SW Caribbean along the monsoon trough and tropical wave discussed above. For the forecast, surface ridging over the western Atlantic will continue to support moderate to fresh trade winds across the east and central Caribbean through mid week, with fresh to strong winds pulsing off Venezuela and northwest Colombia. Winds and seas across the basin may increase through late week as the ridge strengthens and broad low pressure forms along Central America. Strongest winds expected to be over the northwest and south-central Caribbean Thu night through the remainder weekend. ATLANTIC OCEAN... A mid-level trough is moving over the western Atlantic, causing scattered showers and isolated thunderstorms from the central Bahamas to Bermuda. Winds are mainly light to gentle in the western subtropical Atlantic with 4-6 ft seas. South of 20N, winds increase to moderate to fresh easterlies with 6-8 ft seas. In the central Atlantic, a 1024 mb high pressure centered near 28N52W dominates the pattern. Winds are light to gentle north of 25N and moderate to fresh south of 25N. Seas are generally 5-7 ft. In the eastern Atlantic, moderate to fresh northerly winds are observed along the coast of Morocco and NE of the Cabo Verde Islands. Seas are generally 6-8 ft. For the forecast west of 55W, a surface ridge along 25N is shifting east ahead of a weak cold front moving across the far NW offshore waters. The front will continue to move eastward over the waters north of 28N between northeast Florida and 55W through late Wed. Weak ridging will build again over the region later in the week, supporting gentle to moderate winds through Sat night, except for moderate to fresh winds N of Hispaniola and the Great Bahama Bank Fri through Sun night. $$ Flynn