John Hammond’s Month Ahead – ‘British Summer Time’? Not so fast…

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

For lovers of cold and snowy weather, this March has been the gift that keeps on giving. Back in 2013, many long weeks of frost and snow made it a record-breaking month. This March, by contrast, the cold hasn’t been relentless. Instead, the bitter wind has come in short sharp bursts.  An off-kilter Stratospheric Polar Vortex has helped conspire to release discrete lobes of frigid air from the arctic air,  interspersed by quite lengthy periods of more benign spring conditions. John and Sara discuss this ‘beastly’ March here. So after a few days of milder weather, is it a case of “here we go again”?

 

MONDAY 26TH MARCH – SUNDAY 1ST APRIL

Mild meets cold: Rain versus snow

The stage is set for a clash of weather systems, the winner of which will determine just how wintry conditions may get as Easter approaches. After a deceptively dry and quiet start to the week, low pressure will be sending mild, wet and windy weather in our direction from the west by Tuesday. But at the same time an arctic high pressure area will be pushing much colder air towards us from Scandinavia. The two will collide somewhere across northern Britain by midweek.

As the cold air begins to gain the upper hand, the rain will be stopped in its tracks and begin to head southwards again. There is a lot of disagreement between computer models about how quickly this takes place, and whether the mild air will stubbornly hold on across the south. Somewhere across the middle of the UK, at the boundary of mild and cold, a wet and chilly start to the Easter Weekend is in prospect, with a non-zero likelihood of some persistent snowfall. Currently, given the inherent uncertainties  it is impossible to nail down details of timing and extent.

If you were hoping that a new month would do the trick, then think again

A White Easter would be a novelty for some and a grim inconvenience for others. But before we get too carried away by some of the inevitable headlines heading our way, I do not expect conditions to become anything like as severe as in recent episodes.

 

MONDAY 2ND APRIL – SUNDAY 8TH APRIL

April showers – some wet, some white

The knife-edge between spring and winter will continue to be close to our shores for a few days. And wherever warm and cold air collide, low pressure can often be found – which isn’t great news for Easter holiday-makers. Both rain and snow is on the menu, and who gets what will depend on the location of that boundary. It looks mostly likely that chilly northerlies will become dominant for a time, pushing any persistent rain or snow away southwards. In its place, we can expect a few days of sunshine and wintry showers. Whilst overnight frost may be widespread, the strong April sunshine by day should prevent snowfall from lasting long on the ground, except on the higher hills.

But the jet stream remains stubbornly far south, as it has been so often through the latter part of winter and early spring. To the north of it, air of arctic origin will prevent any great warm-up. The sun will feel lovely but the air will keep its chill. If you were hoping that a new month would do the trick, then think again.

 

MONDAY 9TH APRIL – SUNDAY 22ND APRIL

Making up for lost time?

As I mentioned in my last blog, signals from computer models often become quite indistinct at this time of year. As northern latitudes heat up, the jet stream becomes much weaker and as a result, weather patterns become more nebulous and slower moving.

However, I expect an accelerated warm-up. With time we’ll lose the direct feed of arctic air; and with milder westerlies, lighter winds and strong sunshine, temperatures will climb – albeit still too slowly for some. I also expect higher pressure to edge in from the southwest, allowing things to dry out.

So there are reasons to be cheerful. By mid-month, spring will be bursting out all over, and the ‘Beast from the East’ will be a fading memory. We hope. With The Grand National in prospect, we’re reminded that the favourite doesn’t always run to form…