Germany, Poland: Adverse weather forecast across northeastern Germany and central, southern, and western Poland through at least early May 23

Thunderstorms are forecast across parts of northeastern Germany and central, southern, and western Poland through at least early May 23. Heavy rainfall, strong winds, lightning, and possible hail may accompany storms. Rainfall totals of up to 9 cm (3.5 inches) and winds gusting up to 80 kph (50 mph) are possible across parts of the affected area. 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 May 22, the German Weather Service (DWD) has issued a red advanced warning (the second highest level on a four-tier scale) for severe thunderstorms for much of Schleswig-Holstein and parts of northern Hamburg, central, southern, and western Mecklenburg-Vorpommern, far eastern Lower Saxony, far northeastern Saxony-Anhalt, eastern and northern Berlin, and eastern and eastern and northern Brandenburg states.

Poland's Institute of Meteorology and Water Management (IMGW) has issued orange thunderstorm warnings (the middle level on a three-tier scale) across Holy Cross, Lesser Poland, and Subcarpatjian provinces, much of Greater Poland, Lodz, Lubuz, and Silesian provinces, and parts of northern Lower Silesian, southern Lublin, southern Masovian, central and northern Opole, and southern and western West Pomeranian provinces. Yellow thunderstorm warnings are in place across the rest of the affected area.

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.