All but the Caribbean coast is expected to have afternoon thunderstorms today.
The country was predicted to be in the gripe of a tropical wave early today. A wave is one of those low-pressure troughs that originate east of the Atlas Mountains in Africa and traverse the globe in tropical latitudes.
The forecast calls for the usual hot and humid mornings with the afternoon bringing heavy rain.
Sunday was generally fair in the Central Valley with some light rain. Saturday saw afternoon and evening rain. San Ramón was hit by a particularly heavy lightning and thunderstorm Saturday afternoon.
The tropical wave is believed to be the first of the season. Typically there are dozens during the hurricane season, and such low pressure areas can cause tropical storms and hurricanes to develop. For Costa Rica, the low pressure can trigger storms when the air is saturated with humidity from the oceans.