A brief burst of heat may bring 30C next week
I don’t know about you, but I think that summer so far this year has been pretty good. Generally, it’s been dry, with a lot of sunshine and warmth and just a few blips of rainy days.
What hasn’t happened yet this summer is for somewhere in the UK to reach a temperature of 30C (86F). The highest temperature recorded so far this year is 28.7C in eastern parts of England last week.
In order for temperatures to get that high in the UK, the wind needs to come from a south to south easterly direction, in order to pump hot and humid air towards us from nearby continental Europe.
However, this summer the wind has largely been coming from a west to south westerly direction. Even though this brings warm tropical maritime air, because it has travelled a long distance over a relatively cool ocean, its heating potential isn’t quite as great.
During the past week, lots of people have been asking me if there are any signs of a prolonged heatwave coming our way. In a nutshell, no, but there could be a brief burst of heat and humidity next week, bringing a chance of hitting 30C.
A meandering jet stream
At the moment, as would normally be expected in summer, the jet stream is weak and sitting to the north west of the UK, generally steering any cloud and rain to the north of us.
However, next week, it is going to pick up speed and meander further southwards in the middle of the Atlantic ocean.
This will cause an area of low pressure to form a few hundred miles to the west of Ireland, around which winds will flow in an anti-clockwise direction – putting the UK in a south to south easterly wind from midweek onwards.
Effectively, this will act as a scoop, pumping hot and humid air towards us from Spain, causing temperatures get a little higher day by day.
Will we hit 30C?
This is where the uncertainty comes in to play. In order for the temperature to reach 30C, the low pressure to the west of the UK needs to stay there long enough to provide a continual feed of hot and humid air.
However, if the low pressure moves in across the UK quite quickly, then the feed of hot and humid air will get cut off and the likelihood of reaching 30C will be significantly reduced.
The latest information available suggests that Thursday or Friday will see the peak of any heat, before rain and thunderstorms spread in from the west in time for the weekend.
Temperatures are likely to be in the range of 20-24C for Scotland and Northern Ireland, 22-28C for England and Wales, with the greatest chance of 30C in southern parts of England.
In the meantime, you can get the latest five-day forecast on the Channel 4 Weather website. I’ll also be posting regular updates on Twitter – @liamdutton