Met Office weather warning for Hertfordshire thunderstorms

A yellow warning is in place across much of the south of England between 12pm and 8pm (September 20), including Watford, St Albans and Harpenden.

It also reaches just to the edge of Hatfield but does not extend to Welwyn Garden City, Stevenage or anywhere further east.

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The Met Office warning states: “A few thundery showers may be present across southern and southeast England early on Friday, but from the middle of the day they are expected to develop more widely within the warning area.

“Whilst some places will remain dry, where thundery showers do occur, they will bring frequent lightning, gusty winds, potentially some large hail, as well as brief spells of heavy rain.

“15-25 mm of rain fall may fall within an hour, with a very small chance of 30-40 mm falling in three hours.”

The Met Office is advising people to check road conditions before driving, avoid sheltering under trees or other structures that may be struck by lightning, and be prepared for potential power cuts.

It adds that delays to train services are “possible” and some short term loss of power and other services is “likely”.