The Met Office has issued a yellow warning for thunderstorms across parts of the North of Ireland this weekend.
The alert covers counties Derry, Antrim, Armagh, Down and Tyrone from midday to 9pm on Sunday.
Forecasters say heavy rain and hail are likely to develop in some places.
The warning brings a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong wind.
Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services, the Met Office says.
A spokesperson added: “High temperatures on Sunday will trigger a scattering of showers across the warning area, some of which are likely to be torrential and thundery, perhaps bringing a few places 30-40 mm in an hour.
“The odd place, affected by multiple showers, could see more than this, perhaps in excess of 60 mm in a few hours, this being most likely across Wales and central England.
“As well as rain, additional hazards will be hail, strong gusts of wind, and lightning will be additional hazards.
“Despite this, many places in the warning area will remain dry, or only see small amounts of rain, due to the scattered nature of the heaviest showers.”