Will this warm spell last for the Bank Holiday weekend?

There is plenty of chat about how this week will be warming up across the UK with temperatures widely in the twenties Celsius. That will vary from 21C on Tuesday and Wednesday for Scotland and Northern Ireland to a peak in the heat on Wednesday for England and Wales Temperatures are expected to be 22 to 28C, maybe even a touch higher in the southeast. The spring warmth will last for another day or so in parts of Britain, but what about the Bank Holiday weekend?

In true British Bank Holiday style, the weather is set to turn. It doesn’t look awful but it might seem a great shame that there will be sunshine and high temperatures midweek but a decline when many will have a long weekend off work. It’s all down to where our air is coming from.

Recently we have had cool air with chilly nights but strong April sunshine and little rain. We have got used to that edge to the weather where it soon feels cool in the shade, the wind or after dark. That it what has been such a change for this week, the air instantly feels warm even if the skies are a bit cloudy. This air mass is coming up from the south, over land which has clear skies and is being heated each day by the sun. Air from north Africa and Spain.

Later this week that feed will be interrupted.

The models vary with the timing of the transition but fresher air will be arriving from the far northwest on Thursday and reach slowly southwards. Southern Britain could cling onto the rather muggy warmth into Friday but the overall theme at the moment is for that to have gone by Saturday.

So if you are making plans, do bear in mind that the nights, and evenings will be nippy again. By day any sunshine will be strong (and warm) with high tree pollen in places. The risk of wildfire is still a concern as the dry weather continues and fallen vegetation from winter remains readily available as fuel. You will need those clothing layers back, especially if stubborn cloud cover returns or for blustery coasts and hills. Don’t rely on how it looks. 

The GFS model picks up a northerly flow by Sunday night into Monday with colder air continuing to feed down from the Norwegian Sea, the North Sea and returning the UK to that colder edge feeling. The east coast of Britain would see temperatures back down near 8 to 10C in that setup with a good deal of cloud. Western areas could see brighter skies and anywhere that sees the sunshine this time of year can benefit from the warmth of the sun’s rays. However temperatures would struggle at only 12 to 16C, it’s not the 26C expected midweek. 

The ECMWF model keeps some of the warmth lurking close by, over France and the Channel Islands into the weekend. This would allow temperatures in Enlgnad of 17 to 21C  which would still be pleasantly warm on Saturday. Further north there is a more westerly flow over the far north of Britain, so lower temperatures and noticeably cooler nights. The colder air isn’t forecast to plunge down from the north until the middle of next week with a touch of frost possible. 

Rather than high pressure over mainland Europe, there will be a high pressure centred to the north of Scotland or northwest of the UK. This would continue the run of dry weather. Frontal rain might wave up from the south on Saturday but there is uncertainty about this feature five days ahead. The warmth might cling on in southern England until Saturday but overall it looks like a shift back to more seasonal weather for the long weekend.