Jet streams–concentrated wind bands in the upper atmosphere–travel around the globe. Responding to changes in position and intensity of high and low-pressure weather systems, they shift north, south, or change course. In an extreme northern position, we get cooler and wetter conditions over the British Isles and warmer and drier conditions over the Mediterranean and Balkans. Hotter conditions over the Balkans cause more moisture than normal to evaporate from the Mediterranean Sea and rain down farther north. The jet stream is gradually shifting northward, likely leading to issues with major cereal crops, wildfires, and other types of weather extremes.
news.arizona.edu/news/harvests-wildfires-epidemics-how-jet-stream-has-shaped-extreme-weather-europe-centuries