RT Journal Article T1 June 2017: The Earliest European Summer Mega-heatwave of Reanalysis Period A1 Sánchez Benítez, A. A1 García Herrera, Ricardo A1 Barriopedro Cepero, David A1 Sousa, P. M. A1 Trigo, R.M. AB This paper examines the characteristics of the heatwave that affected western and central Europe in June 2017. Using a novel algorithm, we show that its extension, intensity, and persistence were comparable to those of other European mega-heatwaves, but it occurred earlier in the summer. The most affected area was Iberia, which experienced devastating forest fires with human casualties and the warmest temperatures of the reanalysis period from daily to seasonal scales. The peak of the mega-heatwave displayed an unprecedented warm air intrusion due to a record-breaking subtropical ridge with signatures closer to those of July and August. The atmospheric circulation was the main triggering factor of the event. However, thermodynamical changes of the last decades made a substantial contribution to the event, by increasing the likelihood of surpassing high-temperature thresholds. This episode could be a good example of a coming future, with high-summer mega-heatwaves occurring earlier. PB American Geophysical Union SN 0094-8276 YR 2018 FD 2018-02-28 LK https://hdl.handle.net/20.500.14352/12090 UL https://hdl.handle.net/20.500.14352/12090 LA eng NO ©2018. American Geophysical Union. All Rights Reserved. We acknowledge the Earth System Research Laboratory (ESRL) Physical Sciences Division, Boulder, Colorado, USA for providing the NCEP/NCAR reanalysis data (www.esrl.noaa.gov/psd). This work was supported by the Ministerio de Economía y Competitividad through the PALEOSTRAT (CGL2015-69699-R) and ISIPEDIA (ERA4CS) (PCIN-2017-046) projects. Ricardo M. Trigo and Pedro M. Sousa are supported by project IMDROFLOOD: Improving Drought and Flood Early Warning, Forecast and Mitigation using real-time hydroclimatic indicators, JPND-WaterJPI/0004/2014, financed by FCT/MCTES (PIDDAC). A. Sánchez Benítez was funded by grant FPU15/03958 from the Ministerio de Educación, Cultura y Deporte (MECD). NO Ministerio de Economía y Competitividad (MINECO) NO FCT/MCTES (PIDDAC) NO Ministerio de Educación, Cultura y Deporte (MECD) DS Docta Complutense RD 8 may 2024