The Met Office has issued a nine-hour warning for thunderstorms for parts of England and Scotland. It runs from 1pm to 10pm on Friday (June 24).
The forecasters say there could be heavy rain, lightning and hail in places. There is also a chance of flooding or lightning strikes.
Motorists have been warned about difficult driving conditions and possible road closures. There could also be power cuts, the Met Office warns.
The chief forecaster says: "While many places in the warning area will remain dry, heavy showers and thunderstorms will develop today, becoming most frequent from mid-afternoon and lasting into the evening in places. Where these occur they are likely to produce some locally torrential rain with 20-30 mm possible in one or two hours, and will likely be accompanied by hail in a few places."
UK Met Office forecast
Today: Showers breaking out, some heavy with thunder in northeast England and southeast Scotland. Some sunshine too and still very warm in the east. Rain moving east across Northern Ireland, Wales and southwest England then turning cooler and windier.
Tonight: Showers in northeast dying out. Band of rain, heavy at times, moving northeastwards across most parts, but petering out in south. Turning much cooler after the rain. Windy in west.
Saturday: Rain, locally heavy, across western Northern Ireland. Elsewhere, feeling cooler with sunny spells and scattered blustery showers. These heaviest and most frequent in west with some eastern parts staying dry.
Outlook for Sunday to Tuesday: Sunny spells and scattered showers, heaviest in the north and west, with driest conditions in the southeast. Longer spells of rain into the west on Tuesday. Breezy, and feeling cooler.
