Fig. 5: Composites of spatially extensive preconditioned drought and fire weather years.

a Normalised antecedent precipitation (\({P}_{a}/{\sigma }_{{P}_{a}}\); brown and green shading), sea surface temperature (SST; red and blue shading), 500 hPa geopotential heights (z₅₀₀; black contours starting at ± 5 m and spaced in intervals of 10 m) and 200 hPa velocity potential (ϕ₂₀₀; pink contours starting at ± 5e5 m²s⁻¹ and spaced in intervals of 5e5 m²s⁻¹). The data are anomalies averaged over the six years listed to the left of the panel, selected as the 10% of years with the most widespread drought and fire weather in the Northern Hemisphere. b As in (a) but for fire weather day, FWD_f, anomalies (shading) and three-monthly z₅₀₀ anomalies (contours starting at ± 5 m and spaced in intervals of 10 m). c–f As in (a) and (b) but for the tropics and the Southern Hemisphere. In all panels, precipitation and fire weather data are for the “fire year” (L = f) and “antecedent” (L = a) periods, respectively, which vary spatially (see the text and Fig. 1d). The period used for other variables in the left (right) column is the 12 (three) months ending (centred) on the most common peak FFDI month for the Northern Hemisphere (June), tropics (August), or Southern Hemisphere (January). Solid (dashed) contours indicate positive (negative) anomalies.