Tropical Waves

An eastern Atlantic tropical wave is along 26W, south of 17N, moving westward at 10-15 kt. A few showers are seen near the southern portion of the wave axis.

A central Atlantic tropical wave is along 54W, south of 17N, moving westward at 10-15 kt. Scattered moderate convection is noted from 08.5N to 12.5N between 48W and 56W.

A tropical wave is moving from the eastern to the central Caribbean, along 69W, south of 19N near the eastern tip of the Dominican Republic, moving westward at 15-20 kt. The southern portion is enhancing convection over western Venezuela and the A-B-C Islands.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic through the coast of Mauritania near 18.5N16W and continues southwestward to 07N31W. The ITCZ extends from 07N31W to just off the coast of French Guiana near 06N53W. Widely scattered moderate convection is evident from 05N to 09N between 13W and 47W.

Gulf Of America

Widely scattered showers are in the NW Gulf. Elsewhere, generally dry conditions prevail. The pressure gradient between the ridge over the central Atlantic and lower pressures over Mexico support moderate to fresh SE winds west of 92W. Seas in these waters are 3-5 ft. Gentle to locally moderate winds and slight seas are prevalent in the rest of the basin.

For the forecast, Atlantic ridging will extend westward across the Gulf through the next several days. Moderate to fresh northeast to east winds are expected each afternoon and evening north of the Yucatan Peninsula and into the eastern Bay of Campeche as a trough develops daily and moves westward. Winds are expected to briefly reach strong speeds at times. Moderate to fresh southeast winds are forecast elsewhere in the western and south-central Gulf, with gentle to moderate winds across the remainder of the basin.

Caribbean Sea

Please refer to the Tropical Waves section for details on the wave moving across the eastern Caribbean.

The eastern portion of the eastern Pacific monsoon trough extends from northern Colombia to Costa Rica and it is the source for scattered showers and isolated thunderstorms across the SW Caribbean Sea, with a 1009 mb embedded low pressure analyzed near 10N80W. Low-level convergence as well as a passing tropical wave is producing scattered showers and isolated thunderstorms elsewhere in the southern Caribbean, mainly S of 14N, while generally drier conditions are noted elsewhere due to a plume of Saharan dust.

A strong subtropical ridge centered north of the islands forces fresh to locally strong easterly trade winds across much of the Caribbean, especially south of 19N, except in the SW Caribbean and offshore much of Cuba where winds are moderate or weaker. Seas are 6-8 ft across the eastern and central Caribbean, with locally higher seas through Atlantic passages due to easterly swell in the Tropical N Atlantic waters. Seas are 4-7 ft over the remainder of the basin.

For the forecast, the pressure gradient between high pressure N of the basin and relatively lower pressures in the Caribbean and in northern South America will maintain fresh to strong trades and moderate seas over most of the central Caribbean and west-central Caribbean through the forecast period. Moderate to rough seas produced by these winds will shift westward toward Honduras and northeast Nicaragua also through the period. Winds will pulse to fresh to strong speeds near the Gulf of Honduras during the evening and overnight hours, with greater coverage of these winds expected Mon and Mon night. Moderate to fresh winds will prevail elsewhere, except in the lee of Cuba where gentle to moderate winds are expected through early next week. Mostly fresh trades will remain over the Tropical N Atlantic zones through early next week. Moderate to rough seas with these winds will subside late Thu.

Atlantic Ocean

Two tropical waves are moving across the basin as described above.

A 1027 mb subtropical ridge centered a few hundred nautical miles east of Bermuda near 32N58.5W dominates the entire tropical Atlantic. Fresh to occasionally strong easterly winds are noted south of 20N over the open waters, and south of 22N west of 55W over those offshore waters. Fresh to locally strong winds are also offshore Africa north of 17N and between the Cabo Verde Islands. Winds are mainly moderate or weaker elsewhere. For seas, 7-10 ft prevail south of 20N and west of 40W. Seas are mainly 6-8 ft south of 20N and east of 40W. Slight seas, 2-4 ft, are found north of 30N, and from 24N to 30N between 25W and 55W, with 4-7 ft seas elsewhere.

For the forecast west of 55W, a ridge along 31N will change little through the next few days. It will be the main feature controlling the wind regime throughout the region. Pulsing fresh to strong winds are expected north of Hispaniola to near 22N during each late afternoon and at night through the period.

Posted 5 hours ago by NHC Forecaster Lewitsky