Fig. 2.

Anomalous moisture fluxes over local maxima of precipitation reduction around the study regions. a Daily mean precipitation ($\mathrm{mm}/\mathrm{day}$) during climatological summer (1979–2018) (in color shading). The arrows symbolize the quantity and direction of moisture fluxes (${\mathrm{m}}^3/\mathrm{m}/\mathrm{day}$), given in Eqs. 1 and 2. The red boxes bound the three study regions. Precipitation anomaly ($\%$) averaged over all heatwaves days (in color shading) and anomaly of daily moisture fluxes (${\mathrm{m}}^3/\mathrm{m}/\mathrm{day}$) (in arrows) in b Northern Europe, c Western Europe, and d Southern Europe. Spatial coverage with orange dots in b–d are areas with summer precipitation of lower than 0.5 mm per day