Europe: Adverse weather forecast across much of Croatia, Hungary, and Slovenia through at least June 4

Thunderstorms and heavy rainfall are forecast across much of Croatia, Hungary, and Slovenia through at least June 4. Heavy rain, strong winds, lightning, and hail may accompany storms.

As of May 20, authorities have issued the following warnings:

• Orange thunderstorm and heavy rainfall warnings (middle level on a three-tier scale): Northeastern and southern Croatia, southern and northwestern Hungary, and central and eastern Slovenia June 3.

• Yellow thunderstorm and heavy rainfall warnings: The rest of Croatia, the rest of Hungary, and the rest of Slovenia June 3, and Hungary and Slovenia June 4.

Officials could update and/or 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 rain 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 regional airports. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with 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.