The sudden stratospheric warming on February 12, 2018

The image captures an atmospheric extreme event, a so-called sudden stratospheric warming (SSW) that occurred on Feb. 12, 2018. It is visualized through potential vorticity above the North Pole at the 10hPa level (~30km) above the Earth’s surface and consists of a split of the winter polar vortex into two separate vortices that interact with each other. Although the events are not predictable more than a few days in advance due to their complex dynamical behavior, these rare events can have long-lasting impacts on the weather at the surface and can lead to persistent cold spells over Europe. This makes them an important puzzle piece for long-range weather forecasting. There is an ongoing international debate about potential changes in frequency of SSW events with climate change that could have significant impacts on future changes in winter weather for Europe.