During winter time in the Northern Hemisphere, the strong winds around the poles at heights of around 20–40km can suddenly slow down dramatically. After such events, Northern Hemisphere weather can be unusual for several months or even weeks. This is why there is great interest in being able to predict these events, which are known as Stratospheric Sudden Warming events.

The traditional way of forecasting these events is to run full climate models forward in time, similar to every day weather forecasting. However, this is computationally expensive and and the models are not giving reliable forecasts beyond about two weeks. This study explores a new, probabilistic way of prediction based on dynamical arguments. It uses the past evolution of the stratosphere to construct probabilities of occurrence as a function of lead time. The study shows meaningful information can be obtained for an entire extended winter season, which is about ten times longer than traditional model forecasting.  

  • Paper: Jucker, M., & Reichler, T. (2018). Dynamical Precursors for Statistical Prediction of Stratospheric SuddenWarming Events. Geophysical Research Letters, 45. https://doi.org/10.1029/2018GL080691