Portugal, Spain: Adverse weather forecast across northwestern and western Portugal and far northwestern Spain through at least Dec. 8

Heavy rainfall is forecast across much of northwestern and western Portugal and parts of far northwestern Spain Dec. 7. Rainfall totals of up to 8 cm (3.1 inches) are forecast across parts of the affected area. Heavy downpours could trigger flooding in low-lying areas and landslides on unstable slopes. Rough seas are also expected along the Atlantic coast through Dec. 8.

As of Dec. 7, the respective meteorological institutes have issued the following warnings across the affected area:

• Orange heavy rainfall warnings (the middle level on a three-tier scale): Aveiro, Braga, Porto, and Viana do Castelo districts in Portugal and parts of far southwestern and western Galicia Autonomous Community in Spain.

• Yellow heavy rainfall warnings: Coimbra, Leiria, Lisboa, Setubal, Vila Real, and Viseu districts in Portugal and parts of southwestern and western Galicia Autonomous Community in Spain.

• Yellow rough sea warnings: Across much of the affected coastlines in both Portugal and Spain.

Officials could update and 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 severe weather impacts utility networks.

The severe weather may cause transport disruptions throughout affected regions. Floodwaters and debris flows could 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 may temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather may trigger flight delays and cancellations at airports across the affected regions. Authorities may temporarily suspend port operations or close beach fronts along the Atlantic 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.