Recurrent stationary waves in observations and models

We analyse circumglobal Rossby-waves in boreal summer and show that some wavenumbers constitute recurrent hemispheric-wide circulation regimes. The atmospheric organisation associated with such patterns can lead to co-occurring heatwaves and floods in specific regions across the northern hemisphere. Recent examples include the summer of 2018 when several record breaking and persistent heat and rainfall extremes occurred near-simultaneously. Here, we quantify to what extent those patterns increase the likelihood of simultaneous heat extremes across affected regions.