The Causes and Predictability of the 2014 Balkans Flooding

The Balkans had the worst floods since records began 120 years ago. The low pressure system drenching the Balkan Peninsula was associated with a cutoff low that dumped heavy rain in a four day period in May of 2014. While no single extreme weather event can be attributed directly to climate change, there have been many recent examples of destructively heavy downpours and deadly floods around the world in recent months. Is this particular unprecedented event consistent with climate change predictions? In this study, we use a high-resolution version of the GEOS 5 AGCM to examine the predictability and causes of this extreme event. In particular, large ensembles of 1-month long simulations were initiated on May 1 of each year from 2000 to 2014 using MERRA reanalyses for the initial conditions. From the model hindcasts and observational data, the variability and predictability are examined by quantifying how much of the precipitation and surface temperature variability was influenced by sea surface temperature (SST) boundary forcing, general atmospheric conditions and/or other leading modes of internal atmospheric.