467 AXNT20 KNHC 211742 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Sat May 21 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 1700 UTC. ...SPECIAL FEATURES... Heavy Rainfall over Central America and SE Mexico: A broad area of low pressure centered just off the Pacific coast of eastern El Salvador has produced periods of heavy rain during the past 24 hours (20/1700 UTC to 21/1700 UTC) over portions of northern Costa Rica, Nicaragua, Honduras, coastal El Salvador and southern Guatemala, as indicated by a 24-hr infrared satellite loop. The current imagery as of 21/1700 UTC shows scattered moderate to isolated strong convection over NE Costa Rica, the east coast of Nicaragua and far eastern Honduras, with some showers also noted over western El Salvador. Over the next 4 days or so (through Wed 25 May), additional periods of moderate of rain, with locally heavy to extreme rain, are expected over portions of western Panama, Costa Rica, Nicaragua, southern Honduras, El Salvador, southern Guatemala and the Mexican state of Chiapas. There is potential for localized areas of flash flooding and mudslides, especially across mountainous terrain. This is a slow moving weather system. High atmospheric moisture content is expected over the area for the next several days. Please refer to products issued by your local or national meteorological service for more information. ...TROPICAL WAVES... A tropical wave is in the Atlantic with axis along 55W, from 13N southward, moving west at 15-20 kt. Scattered moderate convection is noted from 05N-11N between 51W-58W. ...MONSOON TROUGH/ITCZ... The monsoon trough extends from the Senegal coast near 14N17W to 10N20W to 06N26W. The ITCZ continues from 06N26W to 04N37W to 06N53W. Numerous moderate scattered strong convection is noted from 04N-11N between the coast of Africa and 20W. Scattered moderate convection is occurring within 210 nm N and within 150 nm S of the ITCZ west of 33W. GULF OF MEXICO... An upper-level trough extends from Mississippi southward to the south-central Gulf of Mexico. Upper-level diffluence on the east side of the upper trough is inducing numerous moderate and scattered strong convection covering the NE Gulf of Mexico, north of 25N and east of 89W. Gusty winds and frequent lightning are occurring with these thunderstorms. Buoy 42039 near 28.8N and 86W has been reporting SE winds near 31 kt gusting to 35-40 kt, where seas have recently built to 8 ft. A recent satellite altimeter pass from 21/1130 UTC shows seas of 7 to 8 ft off the coast of Texas, north of 27.5N between 94W-95W. Fresh SE winds and seas of 5-7 ft prevail elsewhere across the basin, except for strong winds and seas to 8 ft near the Yucatan Channel. Smoke from agricultural fires over Mexico continues to spread northward and is producing hazy skies across the western Gulf west of 93W off Mexico and southern Texas, where surface observations are showing 3 to 4 mile visibility. For the forecast, the area of strong thunderstorms over the NE Gulf of Mexico is likely to persist through this afternoon, while slowly migrating W toward the north-central Gulf. Fresh to strong southeast winds along with occasionally rough seas will prevail from the south-central Gulf to the northwest Gulf into Sun between high pressure over the western Atlantic and broad low pressure over southern Mexico and northern Central America. Winds and seas will diminish Sun into Mon as the low pressure weakens, except for pulses of fresh to strong winds off the north coast of the Yucatan Peninsula, mainly at night. Looking ahead, a ridge will build from the western Atlantic across the northern Gulf through mid-week, supporting fresh southeast return flow over the western Gulf. CARIBBEAN SEA... The eastern periphery of a broad circulation over Central America, combined with the east Pacific monsoon trough, is producing scattered moderate isolated strong convection over the western Caribbean from 10N to 16.5N between 80W and 84.5W, including along the east coast of Honduras, Nicaragua and northern Costa Rica. Cloudiness with possible isolated showers prevails elsewhere over the NW Caribbean to the west of Jamaica. Mainly fair weather is found over the eastern and central Caribbean, east of 77W, due to subsidence from mid-level ridging over the area. A recent ASCAT satellite data pass shows fresh to strong E to SE trades over much of the central and western Caribbean. Moderate E trades cover the eastern basin. Buoy 42056 near 19.8N 84.9W recently reported ESE wind 25 kt gusting to 31 kt with 8 ft seas. Seas of 7 to 9 ft are likely currently occurring over the far NW Caribbean to the Yucatan Channel. Seas of 7-10 ft are over the waters in between Colombia and Jamaica, while 4-6 ft seas prevail across the E basin. For the forecast, broad low pressure over Central America will slowly move northwestward through Sun as high pressure builds over the western Atlantic. This pattern will support fresh to strong east to southeast winds and rough seas over the central and northwest Caribbean through Sun. Winds and seas will start to diminish across the basin early next week as the pressure gradient relaxes. ATLANTIC OCEAN... A surface ridge extends east to west from a 1027 mb high pressure near 33N28W to 32N47W to a 1027 mb high pressure near 31N69W to the coast of Georgia. This feature is maintaining light to gentle winds north of 25N between 40W-75W, with 3-4 ft seas. A recent ASCAT satellite wind data pass shows moderate to fresh SE winds from north of Hispaniola through the Old Bahama Channel to South Florida. Currently, seas near the Windward Passage are likely 4 to 5 ft, while 3 to 4 ft seas prevails over the remainder of the western Atlantic. A couple of weak surface troughs over the central Atlantic are inducing some scattered showers north of 23N between 38W-53W. ASCAT shows fresh trades from the ITCZ to 14N between 43W-60W, where seas are likely near 7 ft. Moderate trades and 5-7 ft seas are elsewhere from the ITCZ to 20N between 30W- 60W. Fresh NNE winds and 5-7 ft seas prevail north of 20N between the coast of Africa and 21W. For the forecast west of 55W, the high pressure ridge along 30N will strengthen some through the weekend, then weaken next week. The associated pressure gradient will allow for mainly gentle to moderate winds across the region through the period, except for pulsing moderate to fresh east winds north of Hispaniola through late Sun. Moderate northeast swell may impact the waters east of 60W and north of 25N Sun through Tue. The swell is expected to subside Tue night into Wed. $$ Hagen