The districts of Porto, Aveiro, Braga, Viseu, Vila Real and Viana do Castelo will be under warning between 12:00 on Wednesday and 00:00 on Thursday.
The Portuguese Institute of the Sea and Atmosphere (IPMA) also issued a yellow warning of heavy rain for the Western group (Flores and Corvo) between 6pm today and 9am on Wednesday and for the Central group (Terceira, Faial, Pico, São Jorge and Graciosa) between 09:00 on Wednesday and 00:00 on Thursday.
The yellow warning is issued by IPMA whenever there is a risk situation for certain activities depending on the meteorological situation.