  The current pandemic caused by the coronavirus SARS-CoV-2 is having negative
health, social and economic consequences worldwide. In Europe, the pandemic
started to develop strongly at the end of February and beginning of March 2020.
It has subsequently spread over the continent, with special virulence in
northern Italy and inland Spain. In this study we show that an unusual
persistent anticyclonic situation prevailing in southwestern Europe during
February 2020 (i.e. anomalously strong positive phase of the North Atlantic and
Arctic Oscillations) could have resulted in favorable conditions, in terms of
air temperature and humidity, in Italy and Spain for a quicker spread of the
virus compared with the rest of the European countries. It seems plausible that
the strong atmospheric stability and associated dry conditions that dominated
in these regions may have favored the virus's propagation, by short-range
droplet transmission as well as likely by long-range aerosol (airborne)
transmission.
