Monsoon Trough/ITCZ

The monsoon trough axis enters the Atlantic near the coastal border of Sierra Leone and Liberia, and continues southwestward to 06N18W, where it transitions to the ITCZ to 04N27W to 02N36W and to near 02N46W. Numerous moderate to isolated strong convection is within 60 nm north of the ITCZ between 22W and 27W. Scattered moderate convection is seen from 03N to 06N between 30W-39W, south of the ITCZ to the Equator between 25W-37W and within 30 nm south of the ITCZ between 28.5N-31W.

Gulf Of America

A trough is analyzed from 24N85W to 22N89W and to 24N92W. Isolated showers are near the trough between 85W and 87W. Isolated showers are also east of the trough to the Straits of Florida. A stalled frontal boundary extends from western Cuba to inland the Yucatan Peninsula. Otherwise, broad ridging extends from the southeastern United States southwestward to the western Gulf. Moderate to fresh northeast winds are concentrated over the southeastern Gulf from about 22.5N to 25N between 84W and 89W. Seas of 6 to 8 ft in residual NE swell are over these waters. Light to gentle anticyclonic winds are present over the remainder of the basin, except offshore the Texas coast, where moderate south to southwest winds are present. Seas are 2 to 4 ft across the rest of the of the Gulf, except in the NE Gulf where seas are 3 ft or less.

For the forecast, moderate to locally fresh west to northwest winds and moderate seas will develop in the NE Gulf late this afternoon as a dry cold front moves across the southern Unites States. The front will cross the northern Gulf waters tonight into early Thu, with winds turning to the northwest to north in direction behind the front. Otherwise, moderate or weaker winds and slight seas are expected over the remainder of the Gulf into early Sun as weak high pressure prevails over the basin. Later on Sun and Sun night, it presently appears that another cold front may move across the basin, followed by stronger winds.

Caribbean Sea

A stationary front stretches southwestward from the Great Bahama Ban to across western Cuba, across the Yucatan Channel into the Yucatan Peninsula. Isolated weak showers are possible near the front. Ahead of the front, isolated small showers and thunderstorms are seen from 18N to 22N between 80.5W and 84W. A trough is analyzed from near 18N81W to 11N79W. Isolated weak showers are also from 14N to 18N between 77W and 83W. Scattered showers and isolated thunderstorms are confined to south of 11N between 77W and 82W. Overnight scatterometer satellite data passes indicate fresh to strong trade winds present over south-central Caribbean waters while moderate to fresh trade winds are elsewhere east of about 80W. Seas are 6 to 8 ft with the fresh to strong trade winds, 5 to 7 ft elsewhere over the central Caribbean and 4 to 6 ft elsewhere east of 80W. Light and variable winds are west of 80W along with seas of 2 to 4 ft in southeast swell, except for higher seas of 4 to 6 ft in a north to northeast swell between the western tip of Cuba and the northeast part of the Yucatan Peninsula.

For the forecast, fresh to strong trade winds in the central Caribbean will expand to across the eastern Caribbean by late Fri and into the weekend as a tightening pressure gradient develops between lower pressures in northern South America and in the southwestern Caribbean, a stalled front that extends from western Cuba to inland the Yucatan Peninsula and building high pressure in the central Atlantic. Winds will pulse to strong speeds offshore of northern Colombia and in the Gulf of Venezuela nightly through this weekend, with winds possibly reaching near gale at times. Elsewhere, fresh to locally strong trade winds over the tropical Atlantic waters will continue into this weekend while funneling through the passages. New E swell will support rough seas over this region through this weekend.

Atlantic Ocean

A cold front extends from the north-central Atlantic southwestward to 31N55W and to 26N69W, where it continues as a stationary front to the central Bahama and to western Cuba. Satellite imagery reveals a large area of scattered moderate to isolated strong convection north of the frontal boundary from 25N to 30N between 71W and 75W. Scattered showers and isolated thunderstorms are evident from 24N to 26N between 75W and 77.5W. Isolated showers and patches of rain are possible elsewhere north of the frontal boundary mainly east of about 80W.

High pressure of 1021 mb high near 27N39W is the dominate feature for the central and eastern Atlantic areas. Its associated pressure gradient is generally providing for gentle to moderate east to southeast winds from 21N to 24N. Seas of 6 to 9 ft in long- period north swell is mixing with an east swell component south of 21N and east of the Lesser Antilles, where fresh to strong trade winds are quite expansive in coverage. To the north, tight gradient between the high and a 992 mb low pressure in the north-central Atlantic is resulting in fresh to strong southwest winds and seas of 8 to 12 ft north of 29N between 52W and 60W. Gentle to moderate winds are over the remainder of the Atlantic basin along with seas of 5 to 7 ft.

For the forecast, the aforementioned cold front will will begin to weaken today. It will continue eastward reaching the eastern forecast waters by Fri. Fresh to strong SW winds and rough seas that precede the front north of 28N and east of 60W will diminish this morning. NW swell associated with this front will expand in coverage over the eastern zones on Thu as it merges with an extensive area of E swell. Seas reaching to around 12 ft will be possible north of 30N and east of 62W this morning before shifting E of the area. Seas elsewhere will gradually subside from W to E into early Thu. Looking ahead, fresh to strong SW winds along with rough seas will develop offshore of northern Florida by this evening ahead of a cold front that will be moving across the southern United States. This cold front is expected to move offshore the southeastern U.S. Coast tonight, with fresh to strong NW winds and rough seas expected in the wake of the front. The front will weaken as it quickly reaching the NE forecast waters on Fri. In its wake, high pressure will become established E to W near 29N into the weekend as yet another frontal boundary attempts to move across the waters east of northern Florida.

Posted 2 hours ago by NHC Forecaster Aguirre