“Potentially thundery” heavy showers are expected to hit Hertfordshire from tomorrow – sparking a weather warning.

Met Office meteorologists have told commuters that their journeys on Thursday morning could be affected and people in some areas may need to be prepared for potential flooding. The yellow warning for rain will be in place from 9pm tomorrow (September 4) until 9am Thursday (September 5).

It covers most of the south of England, including all of Hertfordshire.

The Met Office said: “Whilst there is some uncertainty, and not all areas will be affected, scattered heavy showers on Wednesday evening may merge into longer spells of heavy, showery rain in places through Wednesday night into Thursday morning.

“Where heavy downpours occur, perhaps thundery in places, accumulations of 20 to 40 mm are possible in an hour or two, with the small chance of isolated accumulations over 50 mm, potentially impacting the Thursday morning commute in some areas.”

The Met Office added that anyone who finds themselves outside and hears thunder should find a safe enclosed shelter and not hide under trees or other structures that may be struck by lightning.

There are no other weather warnings in place over the next seven days.