The Met Office has issued a yellow weather warning for the North West on Wednesday, July 19, 2017.
The forecast is predicting scattered thunderstorms with intense downpours in the early hours of Wednesday morning, with the possibility of severe storms breaking out again in the afternoon.
Forecasters are also warning of some localised flooding of homes, businesses and roads.
A spokesman for the Met Office said: "Although many places are likely to miss the worst of the rain, intense downpours associated with the thunderstorms may give over 30 mm in an hour very locally and perhaps 50 mm in 2 or 3 hours.
"As is usual in this type of situation there is considerable uncertainty in the areas that are most likely to be affected.
"Frequent lightning may be an additional hazard with potential for disruption to power networks.
"Large hail may also be an additional hazard on Wednesday afternoon."