On cold spells in North America and storminess in western Europe

Gabriele Messori (1, 2) , Rodrigo Caballero (1, 2) , Marco Gaetani (3)

1 MISU - Department of Meteorology [Stockholm]
2 Bolin Centre for Climate Research
3 TROPO - LATMOS

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.

Keywords: North Atlantic; precipitation; Cold spells; destructive windstorms; jet stream; extreme events

Domains: Climatology

Gabriele Messori, Rodrigo Caballero, Marco Gaetani. On cold spells in North America and storminess in western Europe. Geophysical Research Letters, 2016, 43 (12), pp.6620-6628. ⟨10.1002/2016GL069392⟩. ⟨insu-01327494⟩