000 AXNT20 KNHC 190446 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 0605 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 0000 UTC surface analysis and satellite imagery through 0430 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... An 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 02N to 06N between 32W 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 its NW, scattered moderate to strong convection is evident over the SW Caribbean Sea from 11N to 15N between 78W and 83W. ...MONSOON TROUGH/ITCZ... The monsoon trough exits the African coast of Guinea-Bissau near 12N16W and extends to 06N18W. The ITCZ continues from 06N18W to 03N33W. West of the tropical wave, the ITCZ continues from 02N39W to 00N50W near the mouth of the Amazon River. Scattered moderate convection is observed within 240 nm of the western portion of the ITCZ. The eastern end of the Pacific monsoon trough and an embedded 1012 mb low near 10N75W are aiding in forcing scattered moderate convection near the Panama and Colombia coasts and adjacent Caribbean waters. ...GULF OF MEXICO... The gradient between a 1016 mb high in the NE Gulf and a 1002 mb low over north central Mexico is generating moderate to fresh SE winds in the western Gulf and similar strength E winds in the Bay of Campeche. Buoys are reporting 4-6 ft seas in these areas. In the eastern Gulf winds are light to gentle with 1-3 ft seas. For the forecast, high pressure over the northeast Gulf will shift eastward through Fri, as low pressure develops south of the area over Central America. This pattern will allow an area of moderate to fresh SE winds over the western Gulf to expand eastward across the Gulf by late Fri. Winds and seas will then diminish slightly across most of the basin through early next week as the pressure gradient relaxes, leaving only pulses of fresh to occasionally strong winds at night off the northern and western Yucatan Peninsula. ...CARIBBEAN SEA... Please see the Special Features section for information on a potential heavy rainfall event. In addition to the scattered showers in the SW Caribbean associated with the tropical wave and monsoon trough, a small area of strong convection is noted NW of Jamaica near 19N78W. Moderate to fresh with locally strong easterly trades and 5-7 ft seas are found in the south-central basin from South America to 15N. Gentle to moderate easterly trades with 4-6 ft seas are observed across the eastern, north-central and SW basin. Gentle to moderate SE trades and 1-3 ft seas prevail over the NW basin. 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 Thu, with fresh to strong winds pulsing off northwest Venezuela through early Thu morning. Winds and seas across the basin will increase Thu night into the weekend as the ridge strengthens and broad low pressure forms over Central America. The strongest winds are expected to be over the northwest and south-central Caribbean during this period. Looking ahead, winds and seas will start to diminish over the eastern and central Caribbean early next week as the low weakens. ...ATLANTIC OCEAN... The Atlantic weather pattern is dominated by a 1022 mb high pressure centered near 26N50W. A surface ridge extends along 25N in the western Atlantic. Winds are light to gentle, increasing to moderate easterlies south of 20N. In the eastern Atlantic, an area of fresh to strong winds are observed on scatterometer data off the coast of Morocco near 31N10W. Otherwise, light to gentle winds increase to moderate to fresh south of 20-25N. Seas are 2-4 ft west of 65W, 4-6 ft north of 20N between 35W to 65W and 6-8 ft in the waters south of 20N and east of of 35W. For the forecast west of 55W, the surface ridge along 25N will lift north to 29N through Fri. This pattern will 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 starting late Fri. $$ Flynn