000 AXNT20 KNHC 172106 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0005 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 1800 UTC surface analysis and satellite imagery through 2000 UTC. ...SPECIAL FEATURES... Global models suggest that a broad area of low pressure may form across the western Caribbean and then shift across Central America late this week into the weekend. This is the climatologically favored time of year for these broad low pressure areas, called Central American Gyres, 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 the southern portions of Central America, which will gradually lift northward across portions of Central America and across the waters east of Central America as the monsoon trough lifts northward. There will be the potential for locally heavy rainfall over portions of Central America, especially in regions of enhanced orographic lift. Please refer to products issued by your local weather service for more information. ...TROPICAL WAVES... A tropical wave is analyzed with axis along 29W and south of 11N, moving west at 10-15 kt. Earlier scatterometer data depicted a windshift in the area. Scattered moderate convection is noted from 06N-08N between 23W-27W, and from 02N-17N between 28W-39W. A tropical wave is located in the central Caribbean with axis along 75W and south of 16N, moving west at 10-15 kt. This position corresponds with an area of enhanced moisture seen on total precipitable water imagery. Scattered moderate isolated strong convection is noted south of 15N between 73W-84W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the coast of Africa at the border of Mauritania and Senegal near 16.5N16.5W to 12N24W. The ITCZ is analyzed west of a tropical wave near 03N30W to 01N44W to the northern coast of Brazil near 02N52W. Scattered moderate isolated strong convection is south of 06N between 41W-52W. GULF OF MEXICO... A 1017 mb high pressure is located over the central Gulf near 26N90.5W and dominates the basin. Moderate SE-S winds are noted west of 94W with light to gentle anticyclonic winds east of 94W, except moderate NE near the Yucatan Peninsula. Seas are 1-2 ft east of 94W, and 2-4 ft west of 94W. Mainly fair weather is noted across the basin, except some haze is possible in the SW and west-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. SE winds will increase to moderate to fresh speeds over the far 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. A tighter pressure gradient between these two features will likely result in locally strong winds across the northern Yucatan peninsula offshore waters Fri night into Sun. CARIBBEAN SEA... Please see the Special Features section for information on a potential heavy rainfall event. A persistent surface trough is located in the western Caribbean Sea along 82W/83W. Light to gentle winds and 2-3 ft seas are west of the trough. The pressure gradient between high pressure in the Atlantic and lower pressure over South America is maintaining moderate to fresh easterlies in the central and eastern Caribbean east of 73W, with gentle to moderate winds west of 73W to the surface trough. Seas are 5-8 ft in the south-central Caribbean, and 3-6 ft elsewhere east of the surface trough. Scattered showers and isolated thunderstorms are observed in the SW Caribbean along the monsoon trough and ahead of a 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 as 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 over the central Bahamas and area to the northeast between 60W and 75W. Moderate to locally fresh SW winds are noted in the showers north of 29N between 65W-70W. A stationary front noses into the area through 31N79W to near Amelia Island Florida. Scattered showers and thunderstorms are near the front at the Florida coast and inland. To the east, a 1023 mb high in the central Atlantic near 26N52W is causing gentle to moderate SE flow across the remainder of the sub-tropical western Atlantic, where seas are 4-6 ft, except 3 to 4 ft west of 77W. In the eastern Atlantic, a cold front extends from 31N20W to 29N26W where it transitions to a weakening stationary front through 27N40W to 30N50W. Isolated to scattered moderate convection is possible near and north of the front. Winds are gentle on both sides of the front across the waters north of 23N and east of 55W. Moderate to fresh trades persist south of 23N, locally strong near the coast of Africa from 16N-23N west- southwest through the Cabo Verde Islands. Seas of 5-7 ft in easterly swell dominates the waters south of 23N, locally to 8 ft north of northern South America, with 4-7 ft seas north of 23N in northerly swell, locally to 8 ft along 31N between 20W-35W. For the forecast west of 55W, a surface ridge along 29N will shift east this evening ahead of a weak cold front moving across the far NW offshore waters. The front will continue to move 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 north of Hispaniola and the Great Bahama Bank Fri through Sun night. $$ Lewitsky