John Hammond’s Month Ahead – Here comes the sun… but for how long?!

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

It wasn’t quite the ‘Beast from the East’ but, with a few exceptions, grey skies and a damp chill from the North Sea have continued to hold spring back in recent days. The landscape still resembles February rather than April! And by the time I write my next blog the easterly will be back again.

But don’t panic – this will be an easterly of a very different kind! Warm and dry Continental air is heading our way. Images of blue skies and pink skin will soon abound as temperatures soar into the 20s.

Could this be the start of a long hot summer? As we’ll see, it won’t even be the start of a long hot fortnight. So, enjoy it. There are already signs of another change…

T-shirts, shorts and summer dresses at the ready…

MONDAY 16TH APRIL – SUNDAY 22ND APRIL

Brief but beautiful

Lawnmowers at the ready – things are about to start growing very quickly. A weekend of southwesterly winds will already have ushered in a welcome rise in temperatures, but also a splash of rain from Atlantic frontal systems.

By the start of the new working week, though, big changes will be occurring higher up in the atmosphere. A huge trough in the jet stream over mid-Atlantic will lead to a compensatory surge northwards out of Europe. In response, rain-bearing fronts, still affecting Scotland and Northern Ireland for a time, will also retreat away from the UK. In their place, from the Continent, a dome of dry, sunny and increasingly warm air will steadily take control. By midweek, most places will be enjoying blue skies and temperatures in the high teens or low 20s Celsius. T-shirts, shorts and summer dresses at the ready as the winter woolies are banished at last! But, as Brits bare all, inevitably, many an exposed back will be burnt too – the sun is as strong now as it is in August!

Even higher temperatures may occur in a few places, but not for most of us. At the end of the week, that North Sea breeze will be back, leaving its cool imprint on eastern coastal counties.

By the weekend there are increasing signs that our welcome little bubble of ‘summer’ may burst. The jet stream looks set to shift slowly in from the Atlantic, shunting our dome of warmth away eastwards. Rain will begin to threaten from the southwest as early as Friday; and through the weekend, thundery showers will become more widespread.

As a runner, I’m very aware of how much the weather can impact marathon-running. We’ll be keeping an eye on conditions in London as Marathon day approaches, but at this stage it looks as if the peak of the heat may have passed by then.

 

MONDAY 23RD APRIL – SUNDAY 29TH APRIL

Back to normal

By the start of the new week, the weather will be back to something rather more ‘run-of-the-mill’. The jet stream will have straightened out its kinks for the time being, and will be delivering Atlantic weather systems across the country. For a time, conditions look wettest across the northwest of the UK. Further south and east, once the earlier rain has cleared, there’ll be a good deal of dry weather through the week. Indeed there are indications that high pressure may begin to dominate more widely again as the week progresses.

So I expect plenty of dry weather, but with temperatures down compared with the previous week. Indeed there’s more than a hint that winds will begin to come from a northerly quarter as the weekend approaches – never a very warm direction. So despite some fine days, the nights will be chilly, with some late frosts a possibility.

 

MONDAY 30TH APRIL – SUNDAY 13TH MAY

Typical May weather

Readers of last week’s blog will be aware of my reluctance to trust the output of long-range computer forecasts, especially in the middle of spring. However I am encouraged by their absence of strong westerly winds and active fronts as we head into May. That type of weather pattern is unusual at this time of year. Instead, I go along with the idea of a lot of dry and settled weather.

But ‘dry and settled’ does not necessarily mean ‘hot and sunny’. A northerly bias to the wind may continue, keeping things cool. North Sea coasts may again feel the chill, especially if Continental low pressure systems start to churn in damper, cloudier air back in from the North Sea.

This time of year is often a good time to head to the northwest of the UK for the best of the weather, and I suspect that this May the trait may be repeated.