The jet stream and why it’s too early to write-off summer

13 05 2013

There have been one or two stories in the press today saying we’re in for another washout summer, which would rightly inspire collective misery across the country.

However, it’s a far too early to be writing off any chance of a decent summer season – after all, it doesn’t officially start (for us meteorologists) for more than two weeks (on 1 June).

It appears the news stories are borne out of the current position of the jet stream, a band of fast moving westerly winds high up in the atmosphere. But why is this important?

A quick Jet stream explainer

The jet stream tends to guide the generally wet and windy weather systems which come in off the Atlantic. So, if it’s over us or just to the south, we tend to get a lot of wet and windy weather – which is what we expect through winter.

If the jet is to the north of us, it guides that changeable weather to the north to give us more settled conditions – which is what we expect in the summer.

(You can read a bit more about the jet stream, how it impacted our weather last year, and any potential connections to climate change in a blog story we wrote last year).

What’s going on now?

Right now the jet stream is sitting to the south of the country and it is influencing the unsettled weather we are seeing at the moment.

Forecast chart showing position of the jet stream at midday on 13 May 2013

Forecast chart showing position of the jet stream at midday on 13 May 2013

It’s fair to say that this is roughly the position it was in for extended periods during the exceptionally wet weather that we saw last year, particularly in June.

Crucially, however, the jet stream does move around quite a bit and it can change its track significantly in just a few days. So the current position of the jet stream does not mean that it’s stuck in that position.

Looking ahead

Much like our weather, it’s a huge challenge to predict the exact track of the jet stream more than five or six days ahead, so there’s still a great deal to play for in the outlook for our summer.

In short, it’s far too early to write-off summer 2013 based on the current position of the jet stream.

To get the best information on what to expect you can see the latest detailed forecasts out to 5-days on our website, as well as a general view of what we expect out to 30 days.

You can find out more about the jet stream in our YouTube video.


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15 responses

13 05 2013
derekbeattieimages

This video is private !

13 05 2013
Dave Britton

Apologies that the video is private – We have updated this now.

13 05 2013
Darren Moore

Be great if the video wasn’t private and we could actually watch it

13 05 2013
Dave Britton

Apologies that the video is private – We have updated this now.

13 05 2013
13 05 2013
julesbollocks

Writing off the summer to rain is a little too much to deal with at the moment so I’ll stay optimistic but if the connection between summer Arctic ice loss is the driving factor, 2013 may be 2007- 2012 all over again.

13 05 2013
Dave Britton

It is always best to remain optimistic I find. In the mean time I have added a couple of links to some our Research News articles that you might find interesting. The first is on potential reasons for the chilly start to Spring: http://www.metoffice.gov.uk/research/news/cold-spring-2013. The second is about the Arctic sea ice minima of last year:
http://www.metoffice.gov.uk/research/news/sea-ice-2012. I hope you find these interesting

13 05 2013
Dr Simon Gosling (@simon_gosling)

Do you know where I can get data for past jet stream position over the UK please? Ideally, numerical data as opposed to maps? Thanks

13 05 2013
Dave Britton

Simon, I am afraid I don’t. I suggest that you email Met Office enquiries on enquiries@metoffice.gov.uk who should be able to help. Thanks Dave

13 05 2013
Stephen Haddad (@stevehadd)

The video in the blog story from last year that you linked has been set as private, and thus can’t be watched.
Blog post:
http://metofficenews.wordpress.com/2012/07/12/the-uks-wet-summer-the-jet-stream-and-climate-change/
Video:

13 05 2013
Dave Britton

Apologies, the video has been updated now. Thanks.

13 05 2013
shetlandguy

Up here in the Shetland Islands, it must surely be our turn to have a decent summer. Our record temperature is about 23 degrees C so I’m not asking for a lot !

14 05 2013
Nigel Boldero

Reblogged this on Old School Garden.

19 05 2013
Mark Joseph

Just checke the jetstream for the next 16 day here: http://www.netweather.tv/index.cgi?action=jetstream;sess=

It is set to stay in an unusual southerly extended loop over the UK well into June. Northerly winds look to predominate. May is likely to be about a whole degree below normal to add to the last 8 months with temperatures ‘significantly’ below normal. One more summer like last and we will lose a significant number of our insect species (that cannot repopulate from the south unlike in mainland Europe) I sense a bleak future.

19 05 2013
Mark Joseph

Edit: In fact the Met office forecast to June 16th Shows as much.

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