A yellow weather warning, which is in place from midnight on Tuesday (January 19) until 12pm on Thursday (January 20), covers Lancashire, Cumbria, Blackpool and Blackburn and Darwen.
As well as a yellow alert an amber warning has also been issued, which will overlap central and east parts of the county, including Blackburn, Darwen, Burnley, Ribble Valley, Leyland, Preston and Greater Manchester.
The amber warning is in place from 6am on Tuesday (January 19) until 11.59pm on Wednesday (January 19).
Met Office experts predict that the combination of heavy rain along melting snow across the hills is likely to lead to some flooding.
As well as flooding, people are being warned to expect damage to buildings, difficult driving conditions, travel disruption as well as power cuts and fast flowing or deep flood water.
During the weather warning 40-70mm of rain is expected, with the worst affected areas expected to see 100-120mm, particularly in the southern Pennines and northern Peak District.
A Met Office spokeman said: "A broad area of rainfall will arrive across this region later on Monday and remain across the area for the following 36-48 hours. Rainfall will be heaviest and most persistent across western facing hills.
"Over the course of this time, 40-70 mm of rainfall is expected to fall widely across the warning area, with the potential for 100-120mm across parts of the southern Pennines and northern Peak District.
"The rain will lead to rapid melting of any remaining lying snow across the higher peaks which may add a further 5-10 mm. Strong winds will also accompany the rainfall and may add to travelling difficulties across areas higher and more exposed routes."
This is what to expect:
• Homes and businesses are likely to be flooded, causing damage to some buildings
• Fast flowing or deep floodwater is likely, causing danger to life
• Delays and some cancellations to train and bus services are likely
• Spray and flooding probably leading to difficult driving conditions and some road closures
• A good chance some communities cut off by flooded roads
• Power cuts and loss of other services to some homes and businesses likely