The role of large-scale atmospheric flow and Rossby wave breaking in the evolution of extreme windstorms over Europe
Abstract
We investigate the relationship between large-scale atmospheric flow and the evolution of the most extreme windstorms affecting Western Continental Europe. The 25 most destructive Western Continental European wind storms are selected from a 43-year climatology. 22 of these storms are grouped as having a similar trajectory and evolution. We show that these storms typically occur during particularly strong and persistent positive NAO anomalies which peak approximately 2 days before the storms' peak intensity; the NAO pattern then shifts eastward to a position over the European continent when the storms strike Europe. A temporal composite of potential temperature on the 2-PVU surface suggests that this NAO shift is the result of simultaneous cyclonic and anticyclonic wave breaking penetrating further to the east than during a typical high-NAO event. This creates an extremely intense, zonally-orientated jet over the North Atlantic whose baroclinicity favours explosive intensification of storms while steering them into Western Continental Europe.
- Publication:
-
Geophysical Research Letters
- Pub Date:
- November 2012
- DOI:
- 10.1029/2012GL053408
- Bibcode:
- 2012GeoRL..3921708H
- Keywords:
-
- Atmospheric Processes: Climatology (1616;
- 1620;
- 3305;
- 4215;
- 8408);
- Atmospheric Processes: Synoptic-scale meteorology;
- Natural Hazards: Extreme events (1817;
- 3235)