Story by Isobel Millet.

A yellow weather warning has been put in place by the Met Office today (Monday, August 15) as thunderstorms are expected to wash the heatwave away.

Between now and Wednesday, Twickenham could see "torrential downpours" and the UK's national weather service has alerted all of London to the likelihood that frequent lightning, large hail and flash flooding will replace the recent wildfires.

The weather warning, which came into effect at 10am this morning and will last until midnight on Wednesday, indicates a "slight chance that power cuts could occur" and where flooding or lightning strikes occur, there is a chance of cancellations to train and bus services.

Dan Suri is the Met Office's chief forecaster for today. He said: "The change in weather regime will see the heat of the last few days slip away from the south and east, this will be increasingly replaced with more unsettled conditions with heavy showers, thunderstorms and torrential downpours being key hazards over the UK until Wednesday.

"Although not all places will be affected, where thunderstorms occur there is the potential to for very large rainfall totals, but when that heavy rain is falling on extremely dry ground, the risk of flash flooding is much more pronounced. 

"With no meaningful rainfall in some southern locations since June, soils in these areas have become baked by the sun turning them into hard almost impenetrable surfaces. Any rainfall in these areas won't be able to soak away and instead it will wash off soils and other hard surfaces, creating flash flooding in some areas. This excess water can rapidly inundate some flood-prone areas. Particular areas of cautions are low-lying stretches of road and those areas adjoining sloping fields where water can quickly run off, creating fast-emerging hazards."