Weak instability associated with a surface to low level trough is resulting in partly cloudy to cloudy skies and few scattered showers. A diffluent pattern at the 700mb level allowed for moisture advection across our area early this morning with cloudiness and scattered showers.
A pocket of dry air still persists at mid levels. Moisture should increase at mid levels during Monday to result in increased cloudiness by late Monday into Tuesday. The approach of a trough (backward tilting) should result in increased cloudiness and shower activity across the Grenadines by Monday night. Instability across SVG should be elevated on Tuesday with models indicating rainfall accumulations possibly near 1 inch (20-25 mm), with scattered showers and chance of isolated thunderstorm activity across parts of our islands (SVG).
Meanwhile, a frontal boundary off the USA east coast could deepen into a low by Monday, drifting in the Atlantic Ocean. This deep low could induce further instability across the island chain on Wednesday with gentle south easterly winds.
Moderate (20-28 km/h) easterly breeze can be expected this afternoon, backing overnight to east north-easterly and becoming moderate to fresh (20-40km/h). Wind speeds should decrease during Tuesday with the passage of the next trough, falling to gentle (12-19km/h) by evening. The exit of the trough should be evident with east-southeasterly gentle breeze by Wednesday afternoon.
Mean sea-level pressure may rise slightly (1016 mb) on Monday, but fall (1012-1014 mb) Tuesday and Wednesday with the passage of the trough. Slight to moderate conditions are expected with wave heights up to 1.0 m on the west and up to 1.8 m on the east, in open water. Conditions will be monitored for northerly swells approaching our area by Wednesday night.
Slight haze is expected this afternoon, but gradual thickening of dust concentrations (40-80 ug/m**3) should be noticeable Tuesday, significantly reducing visibility and air quality by Wednesday (160-320 ug/m**3)