No signs of spring warmth returning anytime soon
Following the warmest May bank holiday weekend that most of the UK has experienced in a few years, the weather has switched back to the all too familiar pattern of cloud, wind and rain.
The change from high pressure to low pressure gracing our shores has put more clouds than sunshine in the skies above during the past week, with temperatures a few degrees below where they should be for early May.
Yet again, the jet stream – a fast moving ribbon of air five miles above our heads – is to blame, having dived to the south of the UK. This not only puts us in a feed of colder air, but also steers areas of low pressure in our direction.
Image from EUMETSAT: shows low pressure (swirl of cloud) over Scotland
Low pressure stuck over us
To make matters worse, for much of this week, the same area of low pressure is going to get stuck over us – spinning around bringing showers or longer spells of rain with just occasional rations of sunshine in between.
So why is this area of low pressure getting stuck over us, rather than moving away like it normally would?
The easiest way to explain this is to use an analogy of a spinning top on a conveyor belt in a supermarket, with the conveyor belt being the jet stream and the spinning top the area of low pressure.
Normally, the jet stream would act as a conveyor belt, pushing the low pressure along, keeping it moving. However, this week, the area of low pressure will become separated from the jet stream and get left behind over the UK.
Referring back to the analogy, effectively, the spinning top falls off the conveyor belt, gets stuck and continues to spin around in roughly the same place until it stops spinning.
It’s the continual spinning around of this low pressure that will bring unsettled weather this week, before eventually weakening at the weekend.
So in a nutshell, don’t expect any barbecue weather soon.
Weather trend into June
Looking ahead to the longer term trend for late-May into the beginning of June, there are signs that high pressure may build to the north east of the UK over Scandinavia.
This would give us an easterly wind, which due to travelling over the still relatively chilly North Sea would bring below average temperatures.
Rainfall is likely to be close to average, but with the area high pressure fairly close by, there’s a good chance of some decent drier spells.
As ever, being so far ahead, the detail can change, so keep an eye on my blog for updates or you can follow me on Twitter – @liamdutton