UK weather maps show exact date most of Britain 'disappears' under huge 500-mile storm

Most of the UK is set to disappear under a 500-mile wave of rain following weeks of heatwaves and high temperatures, the latest weather maps have revealed.

WXCharts has forecast storms and wet weather to hit the UK on August 20 and 21, triggering plummeting temperatures. Rain will be heaviest (between 5mm and 10mm an hour) in southwest Scotland (Glasgow), northwest England (Carlisle), north Wales (Conwy), southwest England (Exeter), and southeast England (Colchester, Brighton). It will also rain across the rest of the country, sweeping from the northwest at midnight on August 20 to the southeast at 6am on August 21. During this period, temperatureswill drop as low as 6C in Scotland, 7C in Northern Ireland, Wales and north England, 10C in the Midlands and southwest of England, and 13C in the southeast and East Anglia.

The Met Office long-range weather forecast for August 21 until September 4 says that although dry weather is likely to be prominent, "periods of rain or showers and thunderstorms" are also possible.

It says: "High pressure, and therefore largely settled conditions overall, appears more likely for the second half of August. Although dry weather is likely to dominate, periods of rain or showers and thunderstorms may develop at times.

"Above average temperatures overall seem most likely, with the potential for hot spells to develop, especially in the east and south.

"By early September, there are signals for high pressure to become less dominant with perhaps a greater chance of some rain, though there is some uncertainty in this aspect of the forecast.

However, hot weather is set to return in the coming days, with temperatures in some parts of the UK rising once more above 25C andx even threatening to hit 30C across southern areas at the start of next week.

For the period August 11-20, the Met Office has forecast possible "hot and humid conditions across parts of England in particular".

Towards mid-August, "high pressure is more likely to dominate the weather across the UK", bringing with it plenty of dry weather, although northern areas may see some rain or showers and breezier conditions.

Above-average temperatures are "more likely than not, especially in the south, where it could also be rather humid".