A dramatic change in the UK's weather is underway this weekend as a vast 300-mile-long band of thunderstorms brings an abrupt end to the recent heatwave. Weather maps have turned green with rainfall indicators, signalling widespread storm activity, while the Met Office has issued a yellow thunderstorm warning covering a large swathe of the country.

From Saturday afternoon through to the early hours of Sunday, intense storms are expected to deliver torrential downpours, lightning strikes, large hailstones and strong gusty winds. The warning includes the risk of flash flooding, power outages, and travel disruption as the storm system tracks northeast across the UK.

The yellow weather alert spans several regions including North West and North East England, Yorkshire and Humber, the East and West Midlands, parts of Wales, and southern Scotland.

At least 25 major cities and large towns likely to be affected, here are the regions affected:

• North West England: Manchester, Liverpool, Preston, Carlisle, Warrington

• North East England: Newcastle upon Tyne, Sunderland, Durham, Middlesbrough

• Yorkshire and the Humber: Leeds, Sheffield, York, Hull, Bradford

• West Midlands: Birmingham, Wolverhampton, Coventry, Stoke-on-Trent

• East Midlands: Nottingham, Derby, Leicester

• Wales: Wrexham, Conwy, Llandudno

• Southern Scotland: Dumfries, Galashiels, Hawick

Meteorologists warn that some locations could see up to 30 to 40 millimetres of rain in under two hours, increasing the likelihood of sudden surface flooding in low-lying or poorly drained areas.

Alongside the risk of flooding, transport networks may be disrupted, with delays and cancellations possible on both rail and road services.

Power cuts may also occur due to lightning strikes or fallen trees, and driving conditions could deteriorate quickly due to spray and standing water.

The Met Office has advised the public to remain alert and take precautions where possible.

While not every area within the warning zone will experience severe weather, those that do could face significant localised impacts.

Authorities recommend checking the latest forecasts regularly and avoiding unnecessary travel during peak storm activity, especially during the evening and overnight hours.