000 AXNT20 KNHC 180932 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1205 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 0600 UTC surface analysis and satellite imagery through 0915 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 32W and south of 11N, moving west at 15 kt. A recent ship observation and earlier scatterometer data revealed a weak surface signature and no significant convection is evident at this time near the wave axis. A tropical wave is in the southwest Caribbean with axis along 78W/79W and south of 17N, moving west-northwest at 15-20 kt. This position corresponds with an area of enhanced moisture seen on layered precipitable water imagery. Scattered moderate to isolated strong convection is evident south of 11N between 76W and 78W. ...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 to strong convection is noted from 06N to 10N between 11W and 15W. Scattered moderate convection is also evident from 01N to 04N between 42W and 48W. south of 11N between 76W and 78W. GULF OF MEXICO... 1017 mb high pressure is centered near 26N95W in the north-central Gulf. Buoy data and a recent scatterometer satellite pass is showing moderate to fresh SE winds off the south Texas and northern Tamaulipas coasts, between the high pressure and lower pressure over the Central Plains. Farther south, a ship observation confirms fresh to strong NE winds off the western coast of Yucatan, related to a trough that sets up most night over the Bay of Campeche. Light to gentle breezes are noted elsewhere over the eastern Gulf. Seas are 2 to 4 ft over the western Gulf, and 1 to 2 ft over the eastern Gulf. No significant shower or thunderstorm activity is evident. For the forecast, the high pressure over the central Gulf will maintain gentle to moderate to fresh 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 continue over the western Gulf through Sat, 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 fresh to occasionally strong NE winds will pulse 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. A recent scatterometer satellite pass confirmed fresh to strong trade winds pulsing off the coast of northwest Venezuela and northeast Colombia. Elsewhere, 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 5 to 7 ft across the basin, except 2 to 4 in the northwest Caribbean. Other than the previously discussed shower and thunderstorm activity near the tropical wave, no significant shower or thunderstorm activity is noted. For the forecast, the 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... The subtropical ridge reaches from 1023 mb high pressure centered near 26N48W westward 25N70W. The ridge is shifting eastward ahead of a weak frontal boundary moving eastward over the waters between the Carolinas and Bermuda. This pattern is supporting gentle to moderate winds north of 20N west of 55W with 4 to 6 ft seas in open waters. In the central Atlantic, the dominant ridge north of 20N is supporting light to gentle winds north of 25N and moderate to fresh south of 25N. Seas are generally 6 to 8 ft in Ne to E swell. 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 to 8 ft. For the forecast west of 55W, the surface ridge along 25N is shifting east ahead of a weak cold front moving eastward to the north of 30N through 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 north of Hispaniola and the Great Bahama Bank Fri night through Sun night. $$ Christensen