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 degrees C. These events are analysed here using observational meteorological data from ten major cities in Poland and neighbouring countries, along with 0.25 degrees x0.25 degrees 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 9days in Bialystok to 14days in Warsaw and Poznan.