A status yellow rainfall warning is in place for Donegal this weekend with all of Ireland expected to be hit.
Between 25 and 50mm of rain could fall locally in short showers. There is also a risk of flash flooding and lightning across the afternoon and evening.
People in Donegal are being warned to expect some heavy downpours this afternoon that are expected to continue on until the evening.
Forecasters say the country could even see a thunderstorm ahead of the long weekend.
Met Éireann’s Gerry Murphy is warning drivers there will be poor visibility during downpours in affected areas.
He said: “The potential impact of it is if you have very heavy downpours that mean visibility is significantly reduced for driving and there is the potential for some flash flooding to occur.”