A severe weather alert is in place for heavy rain across large swathes of south-east England with the risk of localised flooding reports Weather.Com.
Up to an inch of rain an hour is predicted during the most intense storms and lightning could also prove to be a hazard.
The yellow level warning, issued by the UK Met Office, covers Essex, Thurrock, Cambridgeshire, Norfolk, Suffolk, Southend-on-Sea, East Sussex, Kent and Medway.
It is in place until about 6pm on Monday evening with the heaviest downpours expected during the afternoon.
Thunderstorms are forecast in the south-east during Monday afternoon (The Weather Company)
The Met Office chief forecaster stated: “Heavy showers are expected to develop early in the day and will likely turn thundery and locally intense.
“Whilst most places will miss the worst, 20 mm of rain in an hour is likely in places, with a low risk of more than 30 mm locally. Lightning could be an additional hazard.
“The public is advised to take extra care.”
Storms are forecast to remain over the south-east for much of Monday night before
Forecaster Katie Greening, of The Weather Channel, said showers would begin to develop during Monday afternoon becoming heavier as the day progressed.
She said: “Showers are forecast on Monday. These will develop over the south-east during the morning and become heavy as the day progresses with a risk of thunder.
“There will be a better end to the day with showers clearing away from around 6pm.
“It will be a disappointing day on Tuesday with mainly cloudy conditions and spells of light rain and drizzle as another front moves eastwards over the UK.
“These damp conditions are expected to continue through the evening and overnight.”
The remainder of the week looks more settled with dry, sunny spells and temperatures climbing into the low 20s C.