The August 2015 mega‐heatwave in Poland in the context of past events

This paper provides a meteorological overview of the 2015 mega‐heatwave (MHW) over Poland and compares the event with other MHWs in the region since World War II (up until 2015). A mega‐heatwave is defined as an event with at least 6 consecutive days with a maximum air temperature in excess of 30°C. These events are analysed here using observational meteorological data from ten major cities in Poland and neighbouring countries, along with 0.25° × 0.25° analysis fields from the Global Forecast System (GFS). Although the various events had different regional characteristics, in general they were caused by the inflow of a hot tropical air mass from the south, and were perpetuated by a high‐pressure system to the east of Poland and in some cases a low‐pressure system to the west. The 2015 MHW was the most extreme of the studied events, lasting from 9 days in Bialystok to 14 days in Warsaw and Poznan.