000 AXNT20 KNHC 211721 TWDAT Tropical Weather Discussion NWS National Hurricane Center Miami FL 1805 UTC Wed Apr 21 2021 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 32N. 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. ...MONSOON TROUGH/ITCZ... The monsoon trough passes through the coast of Guinea near 11N15W to 03N22W. The ITCZ continues from 03N22W to the coast of Brazil near 00N50W. Scattered moderate and isolated strong convection is from 05S northward to 180 nm north of the ITCZ and monsoon trough, between the coast of Africa and 36W. Isolated moderate convection is from 01S-08N between 42W-57W. GULF OF MEXICO... A stationary front extends over the southern Gulf of Mexico from Lake Okeechobee Florida to 21N94W. Scattered moderate and isolated strong convection is within 90 nm of the stationary front, north of 23N and east of 88W. Scattered showers and isolated tstorms are over the southern half of the Florida Peninsula. The stationary front will move SE as a cold front this afternoon, exiting the Gulf this evening. Expect for scattered showers and thunderstorms to continue over the southeast Gulf waters near the front through this afternoon. Seas will be in the 3-5 ft range over most of the basin this afternoon. Farther north, a cold front extends from Destin Florida to 28N89W to 27N94W to the Mouth of the Rio Grande River. High pressure of 1027 mb centered over north Texas is ushering in cooler air behind the cold front, with latest surface observations showing fresh N-NE winds north of the cold front. A recent ASCAT pass also shows a large area of fresh N winds over the central Gulf, in between the two fronts. The cold front will reach from west-central Florida to the central Gulf by late tonight, then weaken early Thu as it reaches from southwest Florida to near 23N90W. On Fri, fresh to strong southerly return flow will develop over the western Gulf, shift to the central Gulf early Sat and diminish late Sat as another cold front enters the far NW Gulf. This cold front will move across the rest of the Gulf through Sun night as it weakens. CARIBBEAN SEA... A recent ASCAT pass on Wednesday morning shows strong trades over the south-central Caribbean, with near-gale force winds within 90 nm of the coast of Colombia. Fresh winds prevail elsewhere over the eastern and central Caribbean. The ASCAT pass shows gentle wind speeds over the Windward Passage, north of Jamaica and south of Cuba. Seas are likely 7-10 ft in the south-central Caribbean, 5-7 ft elsewhere over the eastern and central Caribbean, and 3-5 ft over the NW basin. Overall, dry conditions prevail, except for a few showers east of the Yucatan Peninsula and northern Belize as well as over central Cuba. For the forecast, fresh to strong trade winds over the central Caribbean will diminish slightly late in the week as high pressure over the central Atlantic shifts eastward, except near the coast of Colombia where these winds will persist through the week. ATLANTIC OCEAN... A stationary front extends from a 1014 mb low near 33N69W to Lake Okeechobee Florida. A warm front extends SE from the low to 30N61W, where it transitions to a cold front that extends E to 29N55W to 32N45W. Scattered moderate thunderstorms are seen along and within 90 nm SE of the stationary front over the western Atlantic. Farther east, scattered showers are seen along the warm front and cold front. A surface ridge axis extends across the subtropical Atlantic from 30N25W to a 1025 mb high pressure near 27N36W to a 1024 mb high pressure near 28N56W to the central Bahamas. Mainly moderate wind speeds of 10-15 kt prevail across the western Atlantic, except for fresh closer to the 1014 mb low and in the convection along the stationary front. Light to gentle winds prevail elsewhere near the ridge axis over the central and eastern Atlantic, generally from 23N-30N, except near the coast of Africa, where fresh NE winds are observed. A recent ASCAT pass shows fresh trades across the tropical Atlantic, from 06N-21N between 35W-65W. Seas are 4-5 ft over the W Atlantic and across the subtropical Atlantic near the ridge axis. Higher seas of 6-8 ft are located north of 30N east of 75W, and also in the tropical Atlantic, where the fresh trades are observed. For the forecast west of 65W, the west Atlantic stationary front will transition back to a cold front today, and merge with a secondary front emerging off the SE U.S. coast tonight. N of 28N, fresh to strong SW winds are possible ahead of the first front, with strong NW winds possible behind the second front. High pressure will shift eastward through Sat night as a stronger cold front approaches the SE U.S. coast. This front is expected to move across the western Atlantic Sun and Sun night, preceded by fresh to strong southerly winds and possible thunderstorms. Currently, a storm force 998 mb low pressure north of the area near 38N42W extends a cold front SW to beyond 32N45W. The gales associated with this storm will remain north of 32N as it moves ENE over the north Atlantic. However, swell from this storm will produce seas of 11-14 ft, generally north of 28N and east of 40W tonight through Fri. $$ Hagen