On cold spells in North America and storminess in western Europe

• Published in: Geophysical Research Letters
• Main Authors: Messori, Gabriele, Caballero, Rodrigo, Gaetani, Marco
• Other Authors: Department of Meteorology Stockholm (MISU), Stockholm University, Bolin Centre for Climate Research, TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2016
• Subjects: North Atlantic; precipitation; Cold spells; destructive windstorms; jet stream; extreme events; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; Arctic; Pacific; North Atlantic oscillation
• Online Access: https://hal-insu.archives-ouvertes.fr/insu-01327494; https://hal-insu.archives-ouvertes.fr/insu-01327494/document; https://hal-insu.archives-ouvertes.fr/insu-01327494/file/2016GL069392.pdf; https://doi.org/10.1002/2016GL069392

International audience We discuss the dynamical and statistical link between cold extremes over eastern North America and storminess over Western Europe, with a focus on the mid-latitude jet stream, the North Atlantic Oscillation (NAO) and the Pacific-North American Pattern (PNA). The analysis is performed on the European Centre for Medium-Range Weather Forecasts ERA-20C reanalysis. The large-scale circulation associated with the cold spells corresponds to advection of cold air from the Arctic region into North America and to a very zonal and intense North Atlantic jet, shifted persistently south of its climatological location. These features of the Atlantic jet are conducive to destructive windstorms and intense precipitation over a large part of Southern and Continental Europe and the British Isles. The cold spells are preceded by a negative NAO and followed by a positive PNA; however, we interpret the associated circulation anomalies as being distinct from these standard modes of climate variability.