Tropical Waves

A eastern Atlantic is analyzed near 37W, south of 10N, moving westward at 10-15 kt. Isolated moderate convection is found near the wave axis.

An Caribbean tropical wave is analyzed along 75W, south of 15N based on tropical wave diagnostics, moving westward near 10 kt. This wave is currently interacting with lower pressures near Colombia and the eastern end of the Eastern Pacific Monsoon Trough. Thus, scattered to locally numerous moderate to strong convection is depicted south of 10N and over land behind the wave.

Monsoon Trough/ITCZ

A monsoon trough enters the Atlantic the coast near 12.5N16.5W, then curves southwestward to near 03N23W. The ITCZ extends from 03N23W to 00.5N34W. Another portion of the ITCZ then extends from 01N39W to the coast of Brazil at 02N51W. Scattered moderate isolated strong convection is present south of 06.5N and east of 27W. Scattered moderate convection is depicted from 01N to 04N between 27W and 34W, and south of 08.5N between 44W and 53W.

Gulf Of America

A 1025 mb high pressure system centered east of Bermuda extends a ridge into the eastern Gulf waters, supporting moderate or weaker E to SE winds and seas 2 to 4 ft across the eastern half of the basin and southwest portions. Numerous showers and thunderstorms developed earlier this afternoon about a surface trough now extending from the southwest Louisiana coast to just offshore of Tampico Mexico. Areas of heavy rainfall and strong gusty winds associated with this activity have formed an outflow boundary that extends from offshore of central Louisiana the 23N96W. Mid- afternoon satellite scatterometer winds showed strong and gusty winds to near gale-force between the trough and the outflow boundary, where seas have to be locally higher. This convection has since begun to diminish in coverage and intensity.

For the forecast, high pressure extending from the western Atlantic to the northern Gulf will change little during the forecast period. The pressure gradient between it and relatively lower pressures over Texas and northern Mexico will generally maintain a gentle to moderate east to southeast wind flow across the basin through the weekend, with the exception of fresh to strong winds pulsing off NW Yucatan from the late afternoons and into the night time hours. A series of upper-level disturbances moving through a very moist and unstable environment are expected to keep unsettled weather conditions in the form of large thunderstorm complexes, that will be moving ENE across the NW and west-central Gulf sections during the next few days. Mariners transiting through these waters should check the latest forecast and weather conditions prior to beginning or continuing their transits.

Caribbean Sea

A broad ridge, centered on a 1025 mb high located east of Bermuda, extends into the eastern Gulf of America. The resultant pressure gradient is forcing fresh to strong easterly trade winds and seas of 6-9 ft across the central Caribbean. Moderate to fresh easterly breezes and moderate seas are found in the eastern Caribbean and Gulf of Honduras. Elsewhere, light to gentle winds and slight seas are prevalent. Scattered light to moderate showers and moving across the northeast Caribbean, as well as NW portions.

For the forecast, the pressure gradient between high pressure north of the area and relatively lower pressures in northern South America will support fresh to strong trades over the south- central portion of the Caribbean into early next week. These trades will continue to bring rough seas to that portion of the basin. Fresh to strong trades will also pulse each evening over the Gulf of Honduras. Mostly moderate trades will remain elsewhere through the forecast period.

Atlantic Ocean

A broad middle to upper-level low is situated across the N half of the Bahamas and adjacent waters between 70W and 80W. This feature continues to enhance the shower activity between 69W and 75W. The rest of the SW North Atlantic, west of 50W, is under the influence of a broad subtropical ridge centered east of Bermuda. Moderate to fresh easterly winds and moderate seas are noted south of 24N and west of 50W.

A stationary front enters the tropical Atlantic near 31N25W and continues southwestward to 24N50W to 27N63W. A few light showers are evident ahead of this front. The rest of the central and eastern Atlantic is dominated by a broad subtropical ridge anchored by the eastern extension of the 1025 mb high pressure east of Bermuda. A moderate pressure gradient between the aforementioned ridge and lower pressures in western Africa results in moderate to fresh northerly winds from 10N to 25N and east of 30W. Seas there are 4 to 8 ft in NW swell. Elsewhere, moderate or weaker winds and moderate seas prevail.

For the forecast west of 55W, the large middle to upper-level low ENE of the Bahamas will continue to produce scattered to numerous showers and thunderstorms from east of the Bahamas to near 71W, and southward to the vicinity of the Turks and Caicos through early Fri. Some of this activity may contain strong gusty winds and heavy rain reducing visibility. The low is forecast to lift N of the area by early on Fri evening. Southeast winds will pulse fresh to strong speeds north of Hispaniola in the afternoons and evenings going into early next week. Otherwise, high pressure centered just north of the area will maintain rather quite marine conditions through the period.

Posted 0 minutes ago by NHC Forecaster Stripling