Synoptic circulation patterns during temperature extremes in southeastern Europe

This study investigates the synoptic circulation patterns associated with temperature extremes in southeastern (SE) Europe. Using ERA-Interim reanalysis data we report on the typical patterns that characterize the middle and upper tropospheric flow a few days before and during hot and cold extremes. The analysis is done separately for each season, while a further distinction between short-lived and persistent extremes reveals differences and similarities in the associated circulation, as inferred by the spatiotemporal evolution of Rossby wave packets (RWPs). Finally, the performance of ECMWF deterministic forecasts is evaluated for persistent cold and hot extremes during winter and summer respectively. Overall, this work suggests that a correct representation of the RWP evolution is crucial in determining the magnitude and persistence of temperature extremes in SE Europe.
Comment: Included in the Proceedings of the 14th International Conference on Meteorology, Climatology and Atmospheric Physics, October 15-17, 2018, Alexandroupoli, Greece (ISBN 978-960-98220-4-6); v2: Minor correction in figs 2-4, no change in text