The Inter-Tropical Convergence Zone (ITCZ) is positioned near 10o N and upper level conditions are favouring cloud build-ups with showers and thunderstorm activity across that latitude. Additionally, a tropical wave is affecting the extreme southern Windward Islands today. However, a layer of dry air is hindering shower activity within the northern portion of the wave environment.
Our southernmost Grenadine Islands as well as Grenada are experiencing abundant moisture as upper level conditions support scattered moderate convection and isolated thunderstorms, with periods of rain to continue this afternoon. Instability and moisture could spread northward reaching mainland Saint Vincent by evening. As instability lingers, moisture at the mid-levels is expected to enhance shower activity into Thursday morning, with showers decreasing by afternoon.
Ahead of the next tropical wave, a moisture surge with weak instability could move across the region Friday afternoon with some scattered showers.
By late Friday/early Saturday, another tropical wave is expected to approach the eastern Caribbean with favourable upper level trough over our area, occasional cloudiness and scattered showers with periods of rain could intensify by Saturday night.
Mariners can expect slight to moderate seas in open waters with swells on west coast peaking near 1.2 m increasing slightly Friday to 1.5 m, while east coast swells peaking near 2.2 m. Swell heights should generally decrease by late Friday (1.0m - 2.0m).Slight haze with varying intensity can be expected this afternoon thinning out overnight across our area as the wave axis crosses. Hazy conditions can be expected to increase during Thursday afternoon giving way to the next tropical wave late Saturday.