Met Office forecasters say the thunderstorms are likely to bring spells of heavy rain may lead to some travel disruption and flooding. For some areas the rain may be accompanied by thunder and lightning.
Forecasters call for an 80 to 90 per cent chance of rain for much of the day Friday up to around 8 in the evening when drops to around 50 or 60 per cent.
The storm front is also expected to bring cooler temperatures with the high for Friday set for 16C.
While the thunderstorm warning remains in place for Saturday there is less of a chance of rain for the day. There is only around a 10 to 30 per cent chance of rain for Saturday while remaining cloud for much of the day.
Temperatures are expected to warm up slightly Saturday, but remain cooler with a highs around 20C.
But the Father's Day forecast on Sunday will likely bring a bit more sunshine for families to celebrate the day.
There is a 40 to 50 per cent chance of rain in the morning with the afternoon likely expected to brighten up with a partly sunny and partly cloudy forecast.
Temperatures for Father's Day are expected to remain cooler around 19 or 20C.