A glimmer of Bank Holiday sunshine offers a possible respite for waterlogged Britain but not before heavy downpours bring further misery to parts of the UK.

The persistent rain and unseasonably chilly temperatures which have seen this month dubbed “awful August” are likely to give way to warmer weather just in time for the weekend, according to meteorologists.

The break in the clouds will bring particular relief to Northern Ireland, where emergency services are struggling to contain flooding caused by torrential downpours over the weekend.

Some places saw up to three-quarters of the normal August rainfall in a single day, and further storms are forecast for the next few days.

Scotland and northern England can expect heavy rain with possible thunderstorms until Wednesday. Flood warnings were issued for the River Ouse at York and Naburn Lock last night with residents urged to prepare for evacuation.

In Yorkshire, flooding of low-lying land and roads is expected elsewhere along the River Ouse and around the Rivers Aire and Nidd. The West Bay area of Dorset, around Bridport, was also put on alert.

The rest of the country will see clear spells punctuated by showers, though strong winds could bring chaos to southern England and Wales.

Rob Hutchinson, forecaster for weather experts MeteoGroup, said: “I would not be surprised if it is windy enough to cause some disruption. With trees in full leaf and heavy rain weakening soil, it does not take much to bring branches down.”

The unsettled weather looks set to continue on Thursday with periodic showers across the UK, although sunny spells will become more frequent as the weekend approaches.

“The good news is the weather should calm down later in the week,” Mr Hutchinson said. “The Bank Holiday weekend looks quite promising, especially for southern and eastern areas of the UK which might get some nice, warm weather.”

However Paul Simons, The Times's Weatherman, cautioned that the prospect of holiday sun was by no means certain.

"The jet stream is close to, or south of, the UK, which means more wet and windy weather streaming through with intervals of sunshine. However, the different forecasting models are disagreeing with each other on where and when the rain will drop, which shows that the outlook is very uncertain and there's very little confidence in the medium-range forecasts at the moment."

In Northern Ireland any let-up seemed a long way off this weekend, as rivers burst their banks, bridges were washed away and dozens of roads closed amid torrential rain.

Rescue workers battled to evacuate people from flooded homes in Belfast and counties Down, Armagh and Antrim. The Northern Ireland Fire and Rescue Service received over 850 emergency calls from trapped homeowners, while in County Down, the RNLI lifeboat went door to door rescuing residents as waters lapped around their waists.

Some 2,000 people were left without water after a pipe from the county’s Fofanny water treatment works was damaged. Northern Ireland Water said more than 50 major incident response teams had been dispatched to cope with any emergencies.

The province saw travel mayhem after one of the main arterial routes was swamped with 20 million gallons of water on Saturday. The newly-constructed Broadway underpass in Belfast – one of the busiest roads in Northern Ireland as the bypass for the city centre – is not expected to reopen until tonight.

There have been several landslides, including one about a mile from the Spelga Dam on the Slievemaman Road in Newcastle, County Down.

In County Derry, near Tobermore, cattle and sheep were washed away and farmers used trailers to rescue people from flooded houses after the River Moyola burst its banks.

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