Germany, Poland: Adverse weather forecast across the region through at least June 23

Severe weather is forecast across much of Germany and Poland through at least June 23. Thunderstorms are expected across parts of both countries over the coming days, with the most intense storms likely over parts of eastern Germany June 21 and western and southwestern Poland overnight June 21-22. Heavy rainfall, strong winds, lightning, and possible hail may accompany storms. Heavy downpours could trigger flooding in low-lying areas and landslides on unstable slopes. Strong winds may cause property damage and power outages.

As of June 21, the German Weather Service (DWD) has issued a red advanced warning (the second highest level on a four-tier scale) across parts of northeastern Bavaria, southern Brandenburg, southeastern Saxony-Anhalt, Saxony, and central and eastern Thuringia states. Short-term orange thunderstorm warnings are in place for parts of far northwestern Bavaria, central and southern Hesse, and western Lower Saxony states. Orange strong wind warnings are in place for parts of southwestern Baden-Wurttemberg and southern Bavaria, and yellow strong wind warnings are in place across much of southern Germany.

Poland's Institute of Meteorology and Water Management (IMGW) has issued red thunderstorm warnings (the highest level on a three-tier scale) across Lesser Poland, Opole, and Silesian provinces, much of Lower Silesian Province, and parts of southern Greater Poland, southern and western Lodz, and central and eastern Holy Cross provinces. Orange thunderstorm warnings are in place across Lubusz, West Pomeranian, and the rest of Greater Poland, Holy Cross, Lodz, and Lower Silesian provinces, as well as the parts of central, southern, and western Kuyavian-Pomeranian, southwestern Lublin, southern and western Masovian, and central, northern, and western Subcarpathian provinces. Yellow thunderstorm warnings are in place across much of the rest of the country, with the exception of some northeastern areas.

Officials could update and possibly extend the coverage of weather alerts over the coming hours and days.

Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides are possible in hilly or mountainous areas, especially where heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. Disruptions to electricity and telecommunications services are possible where significant flooding or strong winds impact utility networks.

Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. Severe weather could also trigger flight delays and cancellations at airports in the region. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track inundation.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.