The calm start to the weekend will give way to blustery showers as high pressure is shoved aside by cyclonic weather systems. Two arms of a fractured jet stream will grapple with a storm-wreaking area of low pressure to the north of the country.
The region is braced for downpours today before western parts of the UK move into the firing line during the week.
Britons are urged to keep umbrellas to hand on Sunday as an ‘ugly’ weather system ploughs in from the Atlantic.
Met Office meteorologist Alex Deakin said: “During the second half of the weekend, high pressure will be slinking off, and then weather fronts and low-pressure systems merge to bring an ugly looking weather front our way on Sunday.
“The jet stream is split into a northern band and a southern band and there is an area of low pressure that each arm of the jet stream is trying to mix with and trying to push along.
“This area of low pressure has some tropical air in it with some extra energy.
“This will bring some cloud and rain into the northwest on Sunday, but there’s a question mark over whether it’s a little bit further south.”
Winds will continue to batter the country through next week whipping in bands of rain from the Atlantic, he said.
However, it will feel milder than recently thanks to a northerly airflow making way for gusts from the west, he added.
He said: “There is a very strong signal that westerly winds will dominate next week, with low pressure to the north and high pressure to the south generating fairly brisk westerly winds at times.
“The main weather patterns for next week remain solidly that we will see westerly winds dominating which will bring lots of showers in from the west, drier to the east.
And there is a milder signal for next week.”
Temperatures in parts of the country could hit 20C during the second half of the week.
However, a deep low-pressure system will give the nation a rattle going into the weekend, according to Netweather forecaster Ian Simpson.
He said: “Thursday has potential to reach 20C in parts of England, with southerly winds.
“But it looks likely that a deep low pressure system will bring windier and more unsettled weather to all parts of the UK through Friday and into next weekend.”
Weather models show two bands of the jet stream steamrollering towards Britain next week.
Warm air pumped into Canada will distort the jet, pushing low pressure towards the UK amid hints of it turning cooler.
Weathertrending meteorologist John Hammond said: “A more significant change in the weather is likely to begin mid-week.
“As warm air gets pumped up across eastern Canada, it will distort the jet stream, pushing a large area of low pressure down towards us.
“The week will end on a wetter note, and in the wake of this, we begin to suck in Arctic air, so the week will end on a chillier note too.”
Jim Dale, meteorologist for British Weather Services, added: “There will be frontal systems affecting the north and the west next week, but these should stay clear of the south.
“The weather will be bobbing and weaving through the week.”