The Portuguese Institute of the Sea and the Atmosphere (IPMA) informed in a statement on Tuesday that the frontal waves associated with the Leonardo depression will affect the weather in mainland Portugal until Saturday, with periods of persistent and sometimes heavy precipitation, snowfall in the highlands of the North and Centre, strong winds and rough seas.

“For the following days, the passage of new frontal systems and the continuation of this very unstable pattern are expected,” the note states.

This frontal system originates in the south and will gradually extend across the remaining mainland regions today. The period with the highest accumulated precipitation and strongest winds is expected tonight into Thursday, transitioning to showers that may include hail and thunderstorms.

Due to this weather forecast, IPMA (Portuguese Institute of the Sea and the Atmosphere) has issued a yellow warning for sometimes heavy rain for the districts of Évora, Faro, Setúbal, and Lisbon until 3:00 pm today and from that time until 9:00 am on Thursday.

Viseu, Vila Real, Santarém, Viana do Castelo, and Braga are under a yellow warning for rain until 9:00 pm today and then between 3:00 am and 9:00 am on Thursday.

The districts of Bragança, Porto, Guarda, Leiria, Beja, Castelo Branco, Aveiro, Coimbra, and Portalegre will be under a yellow warning due to rain between 3:00 am and 9:00 am on Thursday.

The IPMA (Portuguese Institute of the Sea and the Atmosphere) has also placed the districts of Bragança, Viseu, Évora, Porto, Guarda, Faro, Vila Real, Setúbal, Santarém, Viana do Castelo, Lisbon, Leiria, Beja, Castelo Branco, Aveiro, Coimbra, Portalegre, and Braga under a warning due to wind today and on Thursday, with gusts expected up to 90 kilometers per hour and up to 100 in the mountains.

Porto, Faro, Setúbal, Viana do Castelo, Lisbon, Leiria, Beja, Aveiro, Coimbra and Braga will be under orange alert due to rough seas between 12:00 on Thursday and 18:00 on Saturday, with waves from the west quadrant expected to have a significant height of 5 to 6 meters, potentially reaching a maximum height of 12 to 13 meters.

Due to sea conditions, the maritime bars of Aveiro, Caminha, Douro, Esposende, Figueira da Foz, Vila Praia de Âncora, Póvoa do Varzim, Vila do Conde, Ericeira, Nazaré, São Martinho do Porto, Albufeira and Alvor are closed to all navigation today.

The maritime bars of Leixões, Viana do Castelo, Lisbon and Portimão are subject to restrictions.

The districts of Guarda, Vila Real, Viana do Castelo, Braga and Castelo Branco will be under orange alert between 12:00 and 22:00 on Friday due to snowfall above 800 meters.

Additionally, due to snow, Bragança, Viseu, and Aveiro will be under a yellow alert from 15:00 to 22:00 on Friday.

The orange warning is issued by IPMA when there is a "moderate to high risk weather situation," and the yellow warning when there is a risk of adverse weather for certain weather-dependent activities.