A 1,000-mile wide mass of Arctic air is set to see temperatures plummet in the UK.
Met Office forecaster Marco Petagna said the Arctic Maritime air mass has been moving south over the weekend and will lead to colder temperatures on Monday (May 11).
He warned we are likely to go "from summer back to winter in 48 hours", Gloucestershire Live reports.
Some parts of the UK could see snowfall, although Bristol is not expected to be one of them.
After the heady highs of 24C on Friday (May 8), the Met Office forecasts peak temperatures of just 13C in Bristol on Monday.
Monday should be mostly cloudy with some sunny spells, before a 13C peak on a cloudy Tuesday.
Temperatures should rise to 14C on Wednesday, again expected to be cloudy.
And the rest of the week should grow a little warmer, with 15C highs on both Thursday and Friday, before a 17C peak next Saturday.
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BBC Weather forecaster Sarah Keith-Lucas agrees the UK is set for a cooler week.
She said: "After the recent spell of warm and dry weather across central and Europe things will now be turning colder and more unsettled.
"This is due to the arrival of weather fronts from the Atlantic so there will be some heavy downpours as low pressure pushes across parts of Portugal, Spain and France during Sunday.
"To the north of that, there will be cold winds for the UK and Scandinavia too."
