Croatia, Slovenia: Adverse weather forecast across much of both countries through at least Sept. 6

Severe weather is forecast across much of Croatia and Slovenia through at least Sept. 6. Thunderstorms are forecast to break out across the region over the coming days; heavy rainfall, strong wind gusts, lightning, and possible hail may accompany the storms.

The respective meteorological services have issued the following weather warnings across Croatia and Slovenia Sept. 5-6:

Sept. 5

• Orange thunderstorm warnings (the middle level on a three-tier scale): Rijeka Region in Croatia and southwestern regions in Slovenia.

• Yellow heavy rainfall warnings: Gospic and Rijeka regions in Croatia.

• Yellow thunderstorm warnings: Dubrovnik, Gospic, Karlovac, Knin, Split, and Zagreb regions in Croatia and across the rest of Slovenia.

Sept. 6

• Orange thunderstorm warnings: Knin and Split regions in Croatia.

• Yellow heavy rainfall warnings: Dubrovnik, Knin, and Split regions in Croatia.

• Yellow thunderstorm warnings: Dubrovnik, Gospic, Karlovac, Osijek, and Rijeka regions in Croatia and across Slovenia.

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

The storms could produce rounds of heavy rainfall, strong winds, and isolated thunderstorm activity across the affected areas. 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. Where significant flooding, landslides, or strong winds impact utility networks, disruptions to electricity and telecommunications services are possible.

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. Strong winds might also pose a hazard to high-profile vehicles.

Severe weather could also trigger flight delays and cancellations at airports across the affected areas. Authorities may temporarily suspend port operations or close beach fronts along the Adriatic coast if strong winds trigger hazardous sea conditions. 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.