Meteorologists are studying historical records to try to understand the behaviour of the equatorial jet
Our weather is strongly influenced by what’s happening in the upper atmosphere. For example, high-level equatorial winds, known as the “equatorial jet”, swing between easterlies and westerlies roughly every two years. When they are in their westerly phase, we tend to see stormier and wetter winter weather in northern Europe.
Understanding this pattern helps meteorologists to produce long-term forecasts. But, in 2016, the forecasts went to pot, when the equatorial jet did something unheard of, and flipped from west to east and back to west again, all within the space of six months. Possibly the strong El Niño was to blame but, given that measurements only go back to 1953 and there are no other examples of such a fast switch in the equatorial jet, it is hard to be sure.