Unprecedented atmospheric behavior disrupts one of Earth's most regular climate cycles

"The normal flow of air high up in the atmosphere over the equator, known as the quasi-biennial oscillation, was seen to break down earlier this year. These stratospheric winds are found high above the tropics, their direction and strength changes in a regular two- to three-year cycle which provides forecasters with an indication of the weather to expect in Northern Europe. Westerly winds are known to increase the chance of warm and wet conditions, while easterlies bring drier and colder weather."

"The quasi-biennial oscillation is a regular feature of the climate system. On average, these equatorial eastward and westward winds alternate every 28 to 29 months, making them very predictable in the long term. The team's findings published in Science this week, show that this unexpected change in wind direction was caused by atmospheric waves in the Northern Hemisphere."

"A return to more typical behaviour within the next year is forecast, though scientists believe that the quasi-biennial oscillation could become more susceptible to similar disruptions as the climate warms."

https://www.sciencedaily.com/releases/2016/09/160908151118.htm