As a tropical wave quickly crosses the islands overnight, partly cloudy and hazy skies should become occasionally cloudy with strong breeze pushing few showers supported by moist mid levels into Wednesday. Meanwhile, the presence of the dust and dry air associated with the Saharan Air layer, continue to limit showers across our islands. Dust concentrations of varying intensity should continue into the weekend.
Levels of PM2.5 could peak near 40µg/m3 while PM10 levels could peak near 60 µg/m3 by early morning Wednesday.
A trough in the lower levels just north- east of the island chain could create weak instability late Thursday, with upper level conditions possibly supporting few scattered showers on Friday.
Another tropical wave analyzed near 33W moving west at 10-15 kt (12-17 mph), should be approaching the region during Sunday…. Currently, dust surrounds the wave limiting convection.
Fresh (30 - 40 km/h) breeze from the east north-east should become strong (40-50 km/h) overnight, returning to fresh by Wednesday afternoon and becoming moderate Friday.
Mean sea-level pressure ranging 1016 - 1018 mb should be maintained falling slightly on Friday 1015-1017 mb. Moderate to rough (2.4 - 3.0 m) sea swells on the east coasts and moderate (1.8 - 2.4 m) swells on the west coasts can be expected tonight, retreating by Wednesday afternoon. A marine warning is being issued due to above normal sea swells, strong breeze and reduced visibility in dust haze.... Slight to moderate (1.0 – 2.0 m) swells should return on Friday.
Notes: A large area of showers and thunderstorms over the western Caribbean Sea is associated with a sharp surface trough. This area of disturbed weather is forecast to move westward to northwestward over Central America and the Yucatan Peninsula during the next couple of days, to produce locally heavy rainfall across portions of Nicaragua, Honduras, Belize, Guatemala, and the Yucatan Peninsula through Thursday.
Details on Tropical Storm Aletta and Hurricane Bud in the eastern North Pacific are available at https://www.nhc.noaa.gov/cyclones/.