Yellow alerts for rain and wind have been issued for southern Scotland and Northern Ireland, while a separate alert covering Wales, the Midlands and northern England came into force at 9am today.
Parts of Devon and Cornwall were left underwater with a number of roads being forced closed following the onslaught of showers, with fields across the counties left saturated.
Forecasters say some areas will face frequent showers and even rumbles of thunder through Friday - before a huge bank of rain hits the south-west into Saturday.
The bad weather could cause delays to road, rail, air and ferry transport, and coastal routes, sea fronts and coastal communities may be affected by spray and large waves.