Sunrise over Belfast on Friday morning.
Northern Ireland's second summer heatwave looks set to end with a thunder clap with a "small chance" of flooding in some areas.
The Met Office has issued an 18-hour yellow alert for thunderstorms kicking in at noon on Sunday and going through to 6am on Monday.
Forecasters are warning of disruption.
UTV weather forecaster Louise Small said the warning was not totally unexpected.
"We have a yellow warning in place for thunderstorms on Sunday, however they will be hit and miss.
"We do expect thundery downpours after a hot spell as the atmosphere becomes unstable."
The Met Office said there was a small chance that homes and businesses could be flooded quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds.
"Where flooding or lightning strikes occur, there is a chance of delays and some cancellations to train and bus services," the Met Office said.
"Spray and sudden flooding could lead to difficult driving conditions and some road closures There is a slight chance that power cuts could occur and other services to some homes and businesses could be lost."
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