Sudden heavy downpours could lead to flooding today, the Met Office has warned.
The national forecaster has now issued a severe weather warning, which covers almost the entirety of the north west from 11am until 8pm today.
The alert, which means residents should 'be aware', comes on a busy day for events across the county.
They include Blackpool Pride, the Caribbean Carnival in Preston, and Kirkham and Wesham Club Day.
The St Annes v Blackpool cricket game is also taking place this afternoon.
A spokesman said: "Scattered, heavy downpours will develop today, turning thundery in places. Whilst many places will miss the worst, please be aware of the risk of localised surface water flooding."