Fig. 6: Soil-atmosphere feedbacks during the July HW.

Mean Z500 (m, contours) and TX (°C, shading) anomalies (with respect to 1981–2010) reconstructed for the July HW (23–26 July 2019) from daily flow analogues of Z500 over Europe (solid box in c) preceded by (a) wet (above 66th) and (b) dry (below 33rd) soil moisture conditions at 0–10 cm in WEU (dashed box in c) during the previous 15 days. c Difference between (b) and (a). d Flow-conditioned (dark grey boxes) and random (light grey boxes) distributions of the mean TX anomalies for the July HW over WEU preceded by wet and dry conditions (x-axis). Horizontal dashed line depicts regional mean averaged values observed during the July 2019 HW. e As (d) but for the root-mean-square error (RMSE) distributions of the flow-conditioned (dark grey boxes) and random (light grey boxes) analogues. Boxes and whiskers show the ±0.5·SD around the mean and 5th–95th percentile ranges, respectively, with circles denoting the maximum and minimum values. Data source: NCEP/NCAR reanalysis.