Fig. 3: Wet and dry circulation analogues of the April 2023 heatwave (HW) peak.

Mean Z500 (m, contours) and Tx (°C, shading), presented as anomalies with respect to 1950–2022, reconstructed for the HW peak (26–28 April 2023) from daily flow analogues of Z500 over the western Mediterranean domain (solid box in Fig. 1a). We separate analogues preceded by a wet (above the 66th percentile) and b dry (below the 33rd percentile) average soil moisture conditions at 0–7 cm in the southern Iberian Peninsula (black box in a–c) during the previous 15 days. c Difference between b and a. d Flow-conditioned distributions of the mean Tx anomalies for the April HW peak over south Iberia preceded by wet and dry conditions (y-axis). Vertical black (red) dashed lines depict the regional mean (maximum) values observed during the event peak. Boxes show the interquartile range and whiskers span the 1st–99th percentiles, with points denoting the analogue maximum Tx. e Flow-conditioned distributions as d but for geopotential height anomalies at 500 hPa over the domain used to search analogues shown in Fig. 1a (20W–15E, 25N–50N).