A wet end to the week brings local flooding risk

For many of us so far this week, the weather has been pretty quiet with an area of high pressure covering most of the UK. Whilst the days have been fine with sunshine, the longer nights have led to a touch of frost in places, as well as some mist and fog.

However, the quiet spell of weather is about to come to an abrupt end in the next 24 hours, as an area of low pressure moves across us, bringing heavy rain, brisk winds and a risk of localised flooding.

The cause of the change in weather fortunes is the jet stream – the fast moving ribbon of air high up in the atmosphere that determines how weather systems develop and where they go.

In recent days, it’s been relatively weak across the UK and quite far north, favouring high pressure rather than areas of low pressure.

During the next 24 hours, that is set to change with the jet stream not only pushing further southwards, but increasing in speed.

This will favour areas of low pressure forming to the west of the UK, gradually moving eastwards and giving some areas a significant amount of rain.

With the ground near saturated in some places, further heavy rain will have trouble being absorbed by into the soil and instead run off over the surface.

This could have the effect of causing surface water flooding, as well as making river levels rise sharply as the water quickly runs into river catchments.

On Thursday, Northern Ireland, Wales and western parts of England are at risk from some localised flooding, with 15-30mm, locally 40mm expected.

Overnight into Friday, the risk transfers to eastern parts of Scotland as the rain becomes stuck in the same location for a considerable amount of time. The weather computer models are suggesting that as much as 50-70mm could fall locally.

Beyond Friday, the rain will tend to become showery this weekend, but there are signs that active areas of low pressure will bring further brisk winds and heavy rain to our shores next week.

Don’t forget you can get the latest forecast on the Channel 4 Weather website. If you have any pictures or reports of flooding, you can get in touch with me on Twitter – @liamdutton