South west Hertforshire is set to be battered by heavy rain and hail as thunderstorms hit the county and cause temperatures to plummet.
The county will be lashed by downpours and could be hit by hail showers from lunchtime, according to the Met Office.
Thunder clouds will roll across the capital as temperatures plummet as low as 8C, forecasters said.
The meteorologist said the changeable front was normal for spring as air fronts transition into summer.
Wet weather is set to continue into Thursday morning with cold winds meaning temperatures will his a maximum of 10C.
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