Germany, Poland: Adverse weather forecast to continue across the region through at least May 26 /update 1

Severe weather is forecast to continue across parts of Germany and Poland through at least May 26. Thunderstorms and heavy rainfall are expected across parts of both countries over the coming days. 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 May 23, the German Weather Service (DWD) has issued orange heavy rainfall warnings (the second lowest level on a four-tier scale) for parts of northeastern Mecklenburg-Vorpommern State early May 23. A red advanced warning for heavy rainfall is in place for parts of northern Baden-Wurttemberg and western Bavaria states and a red advanced warning for severe thunderstorms has been issued for parts of southeastern Baden-Wurttemberg and southern Bavaria due to severe weather forecast across southern regions during the afternoon and evening May 23. Further isolated showers and storms are expected in central and southern regions May 24. Heavy rainfall is expected in northern and northwestern regions on May 25, and at times, intense storms are possible across much of the country on May 25 and over the eastern half of the country on May 26.

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 and Lesser Poland provinces, much of Masovian and Subcarpathian provinces, and parts of eastern Lodz, western Lublin, and southeastern Silesian provinces. Yellow thunderstorm warnings are in place across Pomeranian Province and parts of eastern and northern Kuyavian-Pomeranian, east-central, northeastern, and southeastern Lodz, southeastern Lower Silesian, central, northern, and southern Lublin, northeastern and northwestern Masovian, southern Opole, eastern, northeastern, and southern Silesian, northeastern Subcarpathian, central and western Warmian-Masurian, and northeastern West Pomeranian provinces May 23. Further showers and isolated storms are forecast across the country May 24-26.

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.