Norfolk could see thunderstorms and the return of Saharan dust as an ‘African plume’ hits the county.
The weather front is sweeping up from Africa, across France and Spain and into Britain this week.
Dan Holley from Weatherquest, a Norwich-based forecaster, said: "We may see temperatures in the late teens, with highs of 18C.
"But because it will be fairly humid, it's more likely that the warm air will bring some heavy rain.
"Along with that could come some thunderstorms on Wednesday night into Thursday morning.
"Because of where the air is coming from don't be surprised if there's some Saharan dust on cars come Thursday."
The average temperature for this time of year is around 15C, according to the Met Office.
This year is set to be the warmest on record if warmer-than-average temperatures continue.
Dr Mark McCarthy of the Met Office’s National Climate Information Centre said: “It was the warmest year so far up to the end of September, with each month since January being warmer than average."
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