Instability from the shearline currently over the extreme Southern Windward islands will reach St Vincent and the Grenadines by late tonight.
A surface trough is currently located at 55W. These two features coupled with a moist mid to upper level pattern will combine to produce generally cloudy to overcast skies, showers, some of which may be moderate to heavy, periods of rain and isolated thunderstorms. An increase in wind speeds will also produce breezy conditions with occasional gusts during heavy shower activity.
By Wednesday, as this instability moves out of the area, with mid level moisture decreasing, a western Atlantic high pressure system will gradually build across the island chain.(NEMO)