Parts of UK could see half a month's rainfall in a day

Parts of the UK could see half a month's rainfall in a day, with lightning, hail, and gusty winds also forecast.

Heavy, thundery downpours are forecast to hit parts of the UK today, with an amber weather warning for rain in place until 8am for the east of Northern Ireland. Met Office forecaster Simon Partridge said: "It looks like Northern Ireland is the place where we could see the most rainfall and certainly the most impactful rainfall.

"They could see 50 to 75mm of rain within 12 to 18 hours." The country records an average of 89mm of rain in July, meaning more than half a month's rainfall could hit Northern Ireland in less than a day. Forecasters have warned of a risk of flash flooding in County Antrim, Armagh and Down.

It follows a period of already intense rainfall. Saturday's rain brought 47.2mm to Surrey's Charlwood - close to a month's worth.

From 5pm on Saturday to 1pm on Sunday, Scotland's Aboyne recorded 47.6mm. Meanwhile, parts of England and Scotland could see 20-40mm of rain in just two hours today.

The south and east of England are covered by a yellow thunderstorm warning until 9pm. By 11am the same warning will be in place for the Midlands, northern England and Scotland.

More than 20 flood alerts remain active in England and Scotland. "We could see some locally heavy downpours, 20 to 40mm of rain is possible in a couple of hours," Mr Partridge said.

"That is potentially up to around half a month's worth of rain in a couple of hours in some places. "You will see quite a lot of water on the roads and difficult driving conditions.

"Hopefully nothing more significant than that, it certainly won't be an issue for any of the rivers because they are quite low." Low pressure and humid, moist air across the country will cause the heavy, thundery showers, but even within the warning areas some places will stay dry, the Met Office said. Will the warm weather return? This week the weather will remain unsettled, with further thundery downpours across Britain, particularly in the south.

Read more from Sky News:NHS managers who silence whistleblowers to be bannedD-Day veteran who became TikTok star dies aged 102 Daytime temperatures will be average, becoming milder overnight. But as we head into next month there is "only a small chance of hot spells" between 25 July and 3 August, the Met Office says in its long-range forecast.

But warmer weather may return as the month wears on. "There are signs that high pressure to the southwest may try to extend its influence across the UK, which could bring more in the way of dry, settled weather as we head further into August," the weather forecaster says.

"Temperatures will likely continue to be near or above average overall, with a continuing chance of some very warm or hot spells, especially in the south and east, if high pressure wins out for a decent stretch of time.".