High-impact storms during the extended winters of 2018–2021 in the Iberian Peninsula

During the extended winter period from December 2017 to April 2021, the Iberian Peninsula (IP) was impacted by several high-impact storms characterized by intense precipitation and/or strong winds. This study provides a detailed assessment of the events, including synoptic conditions, large-scale dynamics associated with the storms, and a climatological analysis aimed at improving public understanding and preventing natural disasters. The analysis of the cyclones’ variability indicates that their maximum intensity varies between 955 hPa and 985 hPa, with a duration of two to four days, and the most frequent occurrence (eight events) was in January. At the peak of maximum intensity, the composite anomaly patterns showed lower mean sea level pressure (MSLP) values (−21.6 hPa), higher water vapor values (327.6 kg m⁻¹s⁻¹), and wind speed at 250 hPa exceeding 29.6 m s⁻¹ the mean values. Additionally, there were high anomaly values of equivalent potential temperature (θe) of 19.1 °C at 850 hPa, sea surface temperature (SST) anomaly values of −1 °C, and negative anomaly values of surface latent heat flux (Q_E) (−150 W m⁻²) close to the IP. During the days impacted by the storms, the recorded values surpassed the 98th percentile in a significant percentage of days for daily accumulated precipitation (34%), instantaneous wind gusts (46%), wind speed at 10 m (47%), and concurrent events of wind/instantaneous wind gusts and precipitation (26% and 29%, respectively). These findings allow us to describe their meteorological consequences on the IP, particularly the effects resulting from intense precipitation such as floods, and strong winds associated with various destructive impacts. Finally, clear, real-time, and predictive information about weather systems and their impacts is crucial for the public to understand and enable effective responses to mitigate these natural hazards damage.

Keywords: extreme events; extratropical cyclones; explosive development cyclones; winter storms; Iberian Peninsula.

 

Acknowledgments

This work was funded by the Portuguese Fundação para a Ciência e a Tecnologia (FCT) I.P./MCTES through national funds (PIDDAC)–UIDB/50019/2020 (https://doi.org/10.54499/UIDB/50019/2020), UIDP/50019/2020 (https://doi.org/10.54499/UIDP/50019/2020) and LA/P/0068/2020 (https://doi.org/10.54499/LA/P/0068/2020), and project WEx-Atlantic (PTDC/CTAMET/29233/2017, LISBOA-01-0145-FEDER-029233, NORTE-01-0145-FEDER-029233). FCT is also providing for Ana Gonçalves doctoral grant (2021.04927.BD). The EPhysLab group was also funded by Xunta de Galicia, Consellería de Cultura, Educación e Universidade, under project ED431C 2021/44 “Programa de Consolidación e Estructuración de Unidades de Investigación Competitivas.

 

 References

Gonçalves, A.C.R.; Nieto, R.; Liberato, M.L.R. Synoptic and Dynamical Characteristics of High-Impact Storms Affecting the Iberian Peninsula during the 2018–2021 Extended Winters. Atmosphere 2023, 14, 1353. https://doi.org/10.3390/atmos14091353