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

Abstract

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.

Biometeorological conditions during an extreme heatwave event in Poland in August 2015

“…The most frequent and longest heatwaves occur in central and west Poland (Koźmiński and Michalska, ). The longest and most severe heatwaves (described here as mega‐heatwaves) occurred in 1994 and 2015 (Krzyżewska and Dyer, ). The number of heatwaves and hot days are increasing, and heatwaves are becoming longer and more intense (Piotrowicz, ; Kuchcik, ; Wibig et al , ; Kossowska‐Cezak and Skrzypczuk, ; Krzyżewska and Wereski, ; Matuszko and Piotrowicz, ; Owczarek, ; Krzyżewska, ; ).…”

“…These high temperatures were associated with two heatwave events. The first heatwave, the analysis of which is presented in this article, occurred over the period 3–16 August 2015 and was one of the most intense heatwaves recorded in Poland since World War II (Krzyżewska and Dyer, ). This extreme event was the result of an inflow of hot air over Poland, which itself was caused by a high‐pressure system persisting over eastern Europe.…”

The extreme year—analysis of thermal conditions in Poland in 2018

“…During that summer, four heat waves occurred in Poland (Sulikowska et al 2016). The longest one came in the first half of August, and in many stations, it was the longest since World War II (Krzyżewska and Dyer 2018).…”

Anomalously warm months in 2018 in Poland in relation to airflow circulation patterns

“…Zvyagintsev et al ., ; Revich and Shaposhnikov, ). However, owing to the drought that typically accompanies heat, hot weather can have a very severe impact on the economy, especially on agriculture and forestry, as was the case in 2015 (EDO ; Krzyżewska and Dyer ). Droughts cause forest fires, such as those observed in 1992 in southern Poland (Twardosz and Kossowska‐Cezak, ,b).…”