Portugal, Spain: Adverse weather forecast across much of Portugal and parts of western Spain through at least Dec. 1

Heavy rainfall is forecast across much of Portugal, including Madeira but with the exception of northern mainland regions, and parts of western Spain through at least Dec. 1. 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.

As of Nov. 30, 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): Much of Madiera with the exception of Porto Santo in Portugal and parts of far southern Castile and Leon and northern Extremadura autonomous communities in Spain.

• Yellow heavy rainfall warnings: Porto Santo in Madeira and Castelo Branco, Coimbra, Evora, Faro, Guarda, Leiria, Lisboa, Portoalegre, Santarem, Setubal, and Viseu districts in Portugal and parts of northwestern Andalucia, southern Castile and Leon, northwestern Castile-La Mancha, and northern Extremadura autonomous communities in Spain.

• Yellow strong wind warnings: Leiria, Lisboa, Santarem, and Setubal districts in Portugal and parts of southern Castile and Leon, northwestern Castile-La Mancha, and eastern and northern Extremadura autonomous communities in 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. Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas with heavy rainfall and potential track inundation.