Low level instability will linger across the islands, trailing a weak tropical wave. Few scattered showers are likely tonight and Tuesday morning, as the mid to upper levels remain dry. After which, moisture will increase by Tuesday evening as instability from a strong tropical wave approaches the islands. Generally, cloudy skies and showers with the chance of isolated thunderstorms are forecast Tuesday night into Wednesday; intensifying from Wednesday afternoon into Wednesday night as this broad wave moves across Saint Vincent and the Grenadines. Model guidance is indicating approximately 35mm of rainfall accumulation by 8 o’clock Wednesday night. Showers are forecast to continue throughout the night as the wave axis crosses over the islands.
A further 25mm is possible by early Thursday night as the wave moves west north-westward to affect the Northern Windward Islands. Residents and motorists are asked to remain alert. Dry air intrusion is possible around Friday, resulting in mostly fair and hazy conditions.
Seas will remain slight to moderate in open waters with swells peaking at 1.0m on the western coasts and 2.0m on the eastern coasts. Seas will deteriorate during the passage of the wave, with general moderate conditions on both the west and east coasts with swells ranging between 1.5m – 2.5m. A moderate to occasionally fresh (20km/h-35km/h) east north easterly (ENE) wind flow will move across Saint Vincent and the Grenadines from Tuesday into Wednesday, becoming east south east (ESE) and strong (30km/h-40km/h with higher gusts) behind of the wave late Wednesday night into Thursday.