Europe: Adverse weather forecast across much of Austria, Croatia, Hungary, and Slovenia through at least June 1

Thunderstorms and heavy rainfall are forecast across much of Austria, Croatia, Hungary, and Slovenia through at least June 1. 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 30, Austria's Central Institution for Meteorology and Geodynamics (ZAMG) has issued orange rainfall warnings (the middle level on a three-tier scale) across much of Voralberg State in the far west of the country May 30-June 1. Yellow rainfall warnings are in place across much of the rest of western Austria May 30-June 1 and in southern regions May 31. Yellow thunderstorm warnings have been issued across eastern parts of the country May 30-31.

The Croatia Meteorological and Hydrological Service (DHMZ) has issued yellow thunderstorm warnings across Gospic, Karlovac, Osijek, Rijeka, and Zagreb regions May 30. Orange thunderstorm and heavy rainfall warnings have been issued for Gospic and Rijeka regions May 31, as well as yellow thunderstorm warnings across the rest of the country. Yellow strong wind warnings have been issued for all coastal waters May 31.

The Hungarian Meteorological Service has issued yellow heavy rainfall warnings for Szabolcs-Szatmar-Bereg County in northeastern Hungary and yellow thunderstorm warnings across the country May 30. Orange thunderstorm and yellow heavy rainfall warnings have been issued for Baranya and Somogy counties and yellow thunderstorm warnings across the rest of the country May 31. Further yellow thunderstorm warnings are in place across Hungary June 1.

The Slovenia Environment Agency has issued orange heavy rainfall warnings for northwestern and southwestern regions, orange thunderstorm warnings for central, southeastern, and southwestern regions, and yellow thunderstorm warnings for northeastern and northwestern regions May 30. Orange heavy rainfall warnings are in place for central, northwestern, southeastern, and southwestern regions and orange thunderstorm warnings for central, northeastern, southeastern, and southwestern regions May 31, as well as yellow heavy rainfall warnings for northeastern regions and yellow thunderstorm warnings for northwestern regions. Yellow thunderstorm warnings have been issued for northeastern and northwestern regions June 1.

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