Poland braces for severe thunderstorms and hail, IMGW issues second-degree alerts for southern regions

A dynamic weather system is set to sweep across Poland on Tuesday, 9 June 2026, bringing severe thunderstorms, heavy rainfall, hail, and the possibility of isolated tornadoes. The Instytut Meteorologii i Gospodarki Wodnej (IMGW) has issued first- and second-degree warnings covering 13 voivodeships, effective from 1:00 p.m. until 11:00 p.m. The most dangerous conditions are expected in the south, where second-degree alerts are in place for Małopolska and parts of Silesia.

The approaching system

Poland lies in a broad low-pressure trough associated with low Rosi over the North Sea and Norway. Three fronts are moving within this trough: a main cold front, a pre-frontal summer squall line in the warm air, and a secondary cold front behind it. Synoptyk tvnmeteo.pl Arleta Unton-Pyziołek described a band of dynamic weather roughly 600 kilometres wide, which at 8:00 a.m. stretched from Bremen in Germany to Słupsk in Poland, and from Dijon in France to Verona and Udine in Italy. This zone will shift slowly eastward into Poland throughout the day.

This zone will move slowly into Poland during the day, to the east.

Timeline of the storms

Before midday, cumulus clouds will develop over eastern Pomerania, Kujawy, Wielkopolska, Lower Silesia, and Opole Silesia, bringing scattered showers of up to 5 litres per square metre. The main cold front and its broad rain band entered Poland around 9:00 a.m. over the western edges of Lubusz Land and Lower Silesia. By noon, it will cover Western and Central Pomerania, Wielkopolska, Lubusz Land, and Lower Silesia, delivering moderate rainfall of 10–20 l/m². The first lightning strikes will appear in the Izera Mountains and the Izera Foothills.

After 12:00 p.m., thunderstorms will begin to develop over central Pomerania, Wielkopolska, the western edges of Łódź Land, and Lower Silesia. Around 2:00 p.m., the cold front with moderate to heavy rainfall of up to 30 l/m² will extend over eastern and central Pomerania, Kujawy, Łódź Land, Wielkopolska, and all of Silesia. By 4:00 p.m., the front will cover Kashubia, Warmia, Kujawy, western Mazovia, Łódź Land, Silesia, and Małopolska.

Where the danger is greatest

Second-degree warnings apply to Małopolska and parts of Silesia. In these areas, rainfall totals of 20–35 mm are forecast, with local accumulations around 45 mm. Wind gusts may reach 75 km/h, and hail is expected. First-degree warnings cover the remaining 11 voivodeships, where rainfall up to 25 mm, wind gusts to 75 km/h, and hail are possible. The IMGW warns that both alert levels indicate dangerous meteorological phenomena that may cause significant material losses and threaten health and life.

Thunderstorms will occur in a belt from Warmia, through Mazovia, to Silesia and Małopolska. In places they will be accompanied by a violent course of phenomena — heavy and very heavy rainfall with intensities of up to 25–35 mm/h, and in the south of the country up to 45 mm/h.

Supercell risk and evening outlook

Around midday, the first storm cells will initiate. Some will merge over time. Forecasters indicate a likely development of several supercells or mini-supercells in a corridor from Gdańsk Pomerania and Warmia, through Kujawy and Wielkopolska, to Lower Silesia and Opole region. Later in the afternoon and evening, multi-cell formations will enter Western Pomerania, some better organised, with stronger wind gusts possible at their leading edges. Small hail is also possible.

Heat adds to the hazard

Separate first-degree heat warnings are in effect for central and south-eastern Poland, including most of Mazovia and parts of Łódź, Świętokrzyskie, Lublin, and Podkarpacie. Temperatures may reach around 30°C between 2:00 p.m. and 6:00 p.m. The combination of high heat and severe storms increases the risk of violent atmospheric phenomena. Maximum temperatures elsewhere will range from 20°C in the north-west to 25°C in the south-west, with cooler conditions along the coast at 18–20°C.