Sunshine and warmth return to UK this week

A return to warmth

This week will see a return to summer-like warmth across the UK, following last week’s early autumn chill that saw snow fall over the peaks of the Scottish mountains.

Daytime temperatures last week were 4-6C below average, with the chill exacerbated by a brisk northerly wind that brought air from the Arctic. The nights were cold too, with some frost in rural areas, and towns and cities falling as low as 3-5C.

Whilst such cool spells are common in autumn, last week’s was unusually marked for so early in September and stretched very far south into mainland Europe.

Nevertheless, temperatures are on the rise this week, reminding us just how changeable the weather can be at this time of year.

What’s causing the change?

The jet stream this week is going to extend well to the north of the UK. This will allow a big blocking area of high pressure to become established across Scandinavia.

Blocking areas of high pressure do exactly as the name suggests, they block rain-bearing weather systems from moving in off the Atlantic Ocean.

So, much of this week will be dry across the UK with sunny spells. The only exception to this will be the far northwest of Scotland, where cloudier skies will bring a little drizzle.

Whilst there may be some mist, fog and low cloud around in the mornings, this will gradually lift and break for most to reveal brighter skies each day.

How warm will it be?

Given the position and orientation of the blocking area of high pressure, warmer air will be drawn off both the Atlantic Ocean and the nearby continent.

Daytime temperatures this week will generally be in the range of 17-24C, with a few locations potentially a touch warmer.

Initially, the nights will be cool, but overnight temperatures will generally be in the range of 9-14C by the middle of the week.

How long will it last?

The largely fine, dry and warm weather will continue until Friday, which is when some changes start to take place.

By this point, England and Wales will start to see showers and thunderstorms popping up, as an area of low pressure over the Bay of Biscay drifts closer.

Scotland and Northern Ireland will tend to stay settled, although the best of the sunshine will be towards the west. Eastern areas will be prone to mist, murk and low cloud spilling in from the North Sea.

Central Europe floods

Further afield across central Europe – especially Austria, Czechia, Poland and Romania – there has been severe flooding through the weekend, with loss of life and widespread damage and disruption.

The primary cause of the torrential rain has been an area of low pressure that has become detached from the jet stream and stuck over the same region for days.

Some locations have had more rain in four days that they’ve ever had in their wettest autumn on record – the months of September, October and November.

It is very likely that climate change has exacerbated the rainfall event, but scientists will need time to review the data to determine to what degree this has been the case.