Scientists begin to unravel summer jet stream mystery

[Nouska]

Scientists begin to unravel summer jet stream mystery.

http://www.sheffield.ac.uk/news/nr/scientists-unravel-mysteries-of-jet-stream-1.638634

Scientists have discovered the cause of the recent run of miserable wet summers as they begin to unravel the mysteries of the Atlantic jet stream.

Researchers from the University of Sheffield and The Met Office have identified a number of possible factors that may influence the Atlantic jet stream and therefore help to predict summer climate from one year to the next.

The summer weather in the UK and northwest Europe is influenced by the position and strength of the Atlantic jet stream – a ribbon of very strong winds which are caused by the temperature difference between tropical and polar air masses.

A northward shift in the Atlantic jet stream tends to direct low-pressure systems northwards and away from the UK, leading to warm and dry weather during summer.

But, if the summer jet slips southwards it can lead to the jet shifting the low-pressure systems directly over the UK, causing miserable weather like we experienced in the first half of this summer. The big question is “why does the jet stream shift?”

If you want some answers to the question - here's the full paper - are you sitting comfortably - it's a long story.

https://www.researchgate.net/publication/265017222_Drivers_of_North_Atlantic_Polar_Front_jet_stream_variability