John Hammond’s Month Ahead – Holiday Weekend warmth – Is it here to stay?

John gives us his latest thoughts on likely weather trends on the horizon over the next few weeks. To ensure you are reading the very latest weekly blog, check out Wow and Why

My week started with the winter wardrobe being plundered once more, thanks to near record cold for late April. But, as expected, the warmth is coming back in a spring that’s continued to blow hot and cold. I’m in shorts again as I write this blog! So after a fine Bank Holiday Weekend in most places, are we about to lurch back into a mid-May chill? Or are rumours of a long hot spell to be believed?



Thundery breakdown?

This is a week in which I’m more confident about the beginning and the end than I am about the middle. The very warm and settled Bank Holiday weather that most places will have enjoyed will be replaced by cooler and more showery conditions by the following weekend. But the process will be erratic.

The jet stream will make several attempts to dip down and displace the heat that has built up over the UK and near-Continent over the weekend. As a result, fresher Atlantic winds and lower temperatures will be first to arrive in the northwest of the UK by midweek. But progress further southeastwards is much less straightforward. Indeed in the process, one or more plumes of humid thundery air could be sucked northwards ahead of the jet stream, bringing the prospect of some disruptive downpours from Tuesday onwards. As always in this set-up, the stakes are high but the skill of forecast models is low. So over the next few days we’ll be keeping a close eye on the potential for a thundery breakdown.

It’s not until the end of the week that most computer models agree that the warmth will have been swept away from all parts. In its place I expect a cooler, fresher few days with sunshine and showers, especially in the west. When I say cooler, I do not expect a late arctic cold snap.

I certainly don’t expect a washout at Windsor on the 19th!



Wedding weather 

The introduction of cooler Atlantic winds may be temporary. It looks as though the jet stream, having dipped our way, may well retreat back northwards again. Indeed, many longer range forecast models suggest that high pressure will extend across the UK, to ensure plenty of fine and settled weather through the middle of May.

However as I hinted last week, it may well be that the focus of fine weather may shift north across the UK. Further south, lower pressure may bring an increased chance of showers. Of course, with the Royal Wedding¬†approaching, the nation will be hoping the rainclouds stay away. I certainly don’t expect a washout at Windsor on the 19th!



Good growing weather…

As the Whitsun Holiday approaches, there’s a greater chance of showers developing more widely. So outdoor plans may well be affected, and whilst the blooms at the ¬†Chelsea Flower Show will benefit from a watering, visitors may be less grateful. Indeed, for events such as Glyndebourne, waterproofs may be required on some evenings. Some pleasant sunshine is still expected between the downpours, though. And as is often the case at this time of year, with a predominance of easterly winds, northwestern parts of the UK may well fair best. Meanwhile, coastal resorts exposed to breezes off the chilly North Sea may be, well, bracing, to say the least.

Early June is often a time when westerlies make a blustery return to a shores. There’s no clear signal as yet, but I’ll give you my thoughts next week.