Temperatures in Hertfordshire peaked as high as 30 degrees over the weekend, while thunderstorms have been forecast for today.
The Met Office has issued a yellow warning for a thunderstorm from midday to 9pm today.
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According to the Met Office, "flooding of homes and businesses could happen quickly, with damage to some buildings from floodwater, lightning strikes, hail or strong winds".
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"Spray and sudden flooding could lead to difficult driving conditions and some road closures," the warning adds.
Last month a number of our roads were flooded following a huge downpour - including Martins Way and North Road in Stevenage, and Knightsfield Road in Welwyn Garden City.
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