Factors Influencing the Seasonal Predictability of Northern Hemisphere Severe Winter Storms

We investigate the role of the tropics, the stratosphere, and atmosphere‐ocean coupling for seasonal forecasts of strong, potentially damaging, Northern Hemisphere extratropical winter wind storm frequencies. This is done by means of relaxation experiments with the European Centre for Medium‐Range W...

Full description

Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Hansen, Felicitas, Kruschke, Tim, Greatbatch, Richard John, Weisheimer, A.
Format: Article in Journal/Newspaper
Language:English
Published: AGU (American Geophysical Union) 2019
Subjects:
Online Access:https://oceanrep.geomar.de/id/eprint/45092/
https://oceanrep.geomar.de/id/eprint/45092/7/Hansen_et_al-2019-Geophysical_Research_Letters.pdf
https://doi.org/10.1029/2018GL079415
Description
Summary:We investigate the role of the tropics, the stratosphere, and atmosphere‐ocean coupling for seasonal forecasts of strong, potentially damaging, Northern Hemisphere extratropical winter wind storm frequencies. This is done by means of relaxation experiments with the European Centre for Medium‐Range Weather Forecasts model, which allow us to prescribe perfect forecasts for specific parts of the coupled atmosphere‐ocean system. We find that perfect predictions of the Northern Hemisphere stratosphere significantly enhance winter storm predictive skill between eastern Greenland and Northern Europe. Correct seasonal predictions of the occurrence of stratospheric sudden warmings play a decisive role. The importance of correctly predicting the tropics and of two‐way atmosphere‐ocean coupling, both for forecasting stratospheric sudden warming risk and, correspondingly, severe winter storm frequency, is noted.