Special Features

Caribbean Gale Warning: The pressure gradient remains tighten between surface ridging over the western Atlantic and lower pressure in northern South America. This is supporting gale- force northeast to east winds off Colombia through Sun morning. Expect rough to very rough seas to near 15 ft near and downwind of these winds.

Please read the latest HIGH SEAS FORECAST issued by the National Hurricane Center at website https://www.nhc.noaa.gov/text/MIAHSFAT2.shtml for further details.

Heavy Precipitation in South Central America and Colombia: Two tropical waves will propagate into Central America over the next several days. The wave will interact with enhanced divergence aloft and an active monsoon trough. The first wave is located near 87W. As this wave continues westward, expect heavy precipitation to continue in Costa Rica, the Darien region of Panama and into Choco-Colombia on into Sun. On Sun, the second tropical wave will enter the western Caribbean and strengthen the cyclonic rotation over Panama and Colombia that will favor an increase in available moisture into Colombia and moist easterly flow into the eastern portion of Costa Rica. The heaviest precipitation is expected in Costa Rica through early on Sun, while the heaviest precipitation is expected in southwest Panama, the Darien Region, and Choco-Colombia Sun into Monday. There is some uncertainty on how far south the heaviest rainfall could reach, particularly due to how far south the available moisture and the westerly flow enters the region.

Please refer to the WPC International Desk and local weather services for more information.

Tropical Waves

A far eastern Atlantic tropical wave has its axis along 30W from 05N to 21N, moving westward near 15 kt. Scattered moderate convection is ahead of the wave S of 13N to near 33W.

A central Atlantic tropical wave has its axis along 45W from 04N to 21N, moving westward at 15 to 20 kt. Scattered showers are noted in the wave environment.

An eastern Caribbean strong tropical wave is along 67W south of 21N, moving westward at 15 to 20 kt. Scattered moderate convection is noted within 120 nm on either side of the wave axis.

The northern extension of a tropical wave is analyzed along 87W and south of 22N, moving westward at 15 kt. The convection related to this feature is confined to the EPAC waters.

Monsoon Trough/ITCZ

The monsoon trough enters the Atlantic near 21N17W, and extends southwestward to 08N47W, where it transitions to the ITCZ to 08N53W and to near 10N60W. Convection is discussed in the Tropical Waves section above.

Gulf Of America

A 1021 mb high is centered over the north-central Gulf near 29N88W. Its related gradient is supporting gentle to moderate winds across the forecast waters. Seas over the basin are 2 to 4 ft. Fresh winds are occurring north and west of the Yucatan Peninsula and into the Bay of Campeche, as a surface trough extends across the western coast of the Yucatan Peninsula.

For the forecast, the high pressure center will remain over the north- central Gulf through Mon, then moves toward the SE Gulf by Tue while weakening some. This pattern will continue to support mostly gentle to moderate E to SE winds across the basin, with pulses of fresh winds occurring north and west of the Yucatan Peninsula and into the Bay of Campeche each night, as the diurnal surface trough migrates from the Yucatan Peninsula westward across the SW Gulf. Slight to moderate seas are expected through the forecast period.

Caribbean Sea

See the Special Features section for information on a Gale Warning in effect for the waters offshore Colombia.

Refer to the section above for details on the tropical waves moving across the basin.

Outside of the gale area, fresh to strong trade winds and rough seas are over most of the Caribbean south of 18N. Moderate to fresh trades continue over the remainder of the waters along with seas of 4 to 6 ft.

For the forecast, the ridge N of the area combined with the Colombian low will continue to support fresh to strong winds over most of the east and central Caribbean through Sun. Peak winds to minimal gale-force are expected offshore Colombia tonight into early Sun morning. The tropical wave along 67W, will continue to impact the eastern and portions of the central Caribbean tonight. Fresh to strong winds, moderate to rough seas and heavy rain will be associated with the wave, forecast to move across the central Caribbean through Mon, reaching the NW part of the basin Mon night into Tue. Another tropical wave will approach the Leeward Islands by Tue.

Atlantic Ocean

High pressure, anchored by a 1022 mb high center south-southwest of Bermuda near 26N71W continues across the basin. Latest satellite Ascat scatterometer data indicates fresh northeast winds along the coast of western Sahara and through the Canary Islands. Seas are around 6 to 7 ft with these winds. Elsewhere, latest satellite scatterometer data passes reveal moderate or weaker trades. Seas are about 4 to 6 ft with these trades.

Scattered moderate convection is noted N of 28N and W of 53W. A surface trough is analyzed from 31N59W to 27N64W. The base of a broad upper-level trough translating eastward is north of 31N between 50W and 70W, with impulses riding along it from west to east. This activity is also south of a frontal boundary well north of the area.

For the forecast west of 55W, the Bermuda-Azores High, combined with the passage of two tropical waves through the Caribbean Sea will cause fresh to strong NE to E winds south of 22N including the approaches and in the Windward Passage through Sun night. A cold front will slowly push across the northern forecast border east of 70W late on Sun, and move across the northern forecast waters on Mon while dissipating into a trough by Tue. Fresh to strong SW to W winds are expected ahead of the front and E of 70W on Sun and Sun night.

Posted 38 minutes ago by NHC Forecaster Era