Met Office issues 18-hour warning for heavy rain, flooding and thunderstorms

The alert covers a large portion of the British Isles

The Met Office has issued an 18-hour yellow weather warning for rain across Devon and Cornwall. The alert is due to come into force at 6pm tonight (Tuesday) and last until 12pm on Wednesday.

The Exeter-based forecasters say the spells of heavy rain during this period may lead to travel disruption and flooding in some areas. The warning also says that people should expect:

• There is a slight chance of power cuts and loss of other services to some homes and businesses
• There is a small chance that some communities will be temporarily cut off by flooded roads
• There is a small chance that homes and businesses could be flooded, causing damage to some buildings
• Where flooding occurs, there is a slight chance of delays or cancellations to train and bus services
• Spray and flooding could lead to difficult driving conditions and some road closures

The alert is for the whole of Devon and Plymouth, as well as the eastern region of Cornwall, affecting major towns such as St Austell and Launceston. Further afield the warning is also in place for Somerset, Bristol, Gloucestershire, the majority of Wales and as far north as Manchester and Preston. On Wednesday, parts of Northern Ireland are also included in the warning.

The Met Office warning goes on to suggest thunderstorms and lightning could also occur in these areas. It reads: "Areas of heavy rain are expected to develop and push north across the warning area. Rain will develop in southwest England late afternoon, before becoming heavier and expanding north on Tuesday evening and overnight into Wednesday.

"Many places will see around 10-20 mm of rain, but there is a chance some locations may see considerably more than this over a 6 hour period, most likely parts of southwest England and south Wales. A few places may see 50-80 mm of rain fall in 6 hours. Isolated thunderstorms are also possible in the south of the warning area, with lightning an additional hazard."