Isolated showers are possible overnight Saturday, but a drying of the atmosphere is expected by early Sunday. A tropical wave previously tracked to be in our vicinity by Sunday afternoon, is now expected as a weak low level trough with an embedded pocket of dry stable air. Although moisture levels should remain limited, a low level shearline could position just north of mainland St.Vincent
and few scattered showers are possible Sunday night.
Monday afternoon, the chance for scattered showers increases with moisture ahead of an approaching Tropical wave. Scattered showers are expected Monday night and Tuesday, with the tropical wave axis crossing the island chain Tuesday night; thunderstorm activity can be expected with favourable upper level conditions. This tropical wave could have shower and thunderstorm activity increasing east of/across the Lesser Antilles and any development of this system will be monitored. Model projections are currently indicating most of thunderstorm/shower activity across the northern Windward and Leeward Islands by Wednesday/Thursday.
Moderate (20-30km/h) easterly trades should increase by early Sunday morning to fresh (30-40km/h) breeze. Wind direction should veer to east south-easterly during Sunday while decreasing to a moderate breeze. By nightfall, winds should reduce to gentle/moderate (10-25km/h) and back to east north-east with the weak trough. A north-easterly moderate breeze Monday night should announce the approach of the tropical wave, with light winds veering to east south east overnight Tuesday as the axis crosses.
Barometric Pressure could range near 1014 mb - 1016 mb tonight, increasing to 1017 mb by early Sunday before falling by evening to 1013 mb - 1014 mb as the Atlantic High Pressure weakens.
Expect slight to moderate (1.0 m - 1.5 m) easterly swells on both west and east coasts overnight, with slight seas expected by Sunday afternoon (0.5 m – 1.2 m). Effect of winds on ocean water could result in east north-easterly swells Tuesday.