England will be first in the firing line for the deluge this weekend, according to Weather Company forecaster Amy Hodgson.
Southern and southeastern regions will turn wetter and more unsettled on Sunday and into Monday, she added.
She said: “The best of any sunny spells will be across the far southeast on Saturday.
“It will be a blustery day with moderate southeasterly winds across western coasts.
“Sunday will be another unsettled day, however the rain will be more patchy across Scotland, Wales and northern England.
“Outbreaks of rain will continue quite widely on Monday, still under the influence of low pressure under mostly cloudy skies, although there will be some brighter interludes at times.
“High pressure is expected to ridge into the south-west next week while areas of low pressure will continue to arrive over the north and west bringing wetter and windier weather at times here.”
Piers Corbyn, forecaster for WeatherAction, warned to brace for ‘major thunderstorms’ this weekend and into next week.
He said: “It is looking very windy with the risk of gales in parts of the country.“From the middle of the month there are signs of the weather turning again with mostly fine, dry and hot conditions forecast.”
Temperatures are expected to dip into single figures tonight with highs of 23C (73.4F) forecast in the south tomorrow and between 14C (57.2F) and 18C (64.4F) elsewhere.
Weather charts show the mercury pushing into the high 20Cs across southern England next week with Scotland and the north likely to touch 23C (73.4F).