14 Jun 2012

Flood risk returns as more rain heads our way

After a brief respite from the torrential rain that brought severe flooding to parts of England and Wales earlier this week, the risk of flooding is set to return as more heavy rain heads towards the UK.

An area of low pressure that has been developing over the Atlantic Ocean will sweep northwards during Thursday and Friday bringing most places further downpours.

With the ground already saturated from the recent wet weather and some river levels still relatively high, it may not take much rain to cause problems.

The reason for this next spell of wet and windy weather is the jet stream. Having slowed down over the last few days, it’s once again roared to life – pushing low pressure systems towards our shores.

As I discussed in my blog a few days ago, the jet stream is taking an unseasonably southerly track that’s more akin to autumn rather than summer.

More typically at this time of year, the jet stream would generally take a more northerly track which would steer wet and windy weather towards Iceland and Scandinavia, leaving the UK with more settled conditions.

The extent of how unseasonable the wet weather has been so far this month is shown clearly in the amount of rain that has fallen. A few places have seen around double their average June rainfall only half-way through the month;

Percentage of June rainfall up until 12th June

Thorney Island, West Sussex – 234 per cent

Shoreham Airport, West Sussex – 220 per cent

Wiggonholt, West Sussex – 208 per cent

St James’ Park, London – 196 per cent

(Data from the Met Office)

According to a variety of weather computer models in the next two days, much of the UK (except northern Scotland) will see 15-25mm of rain. However parts of Cornwall, north west England, Wales and the east of Northern Ireland could see as much as 40-60mm.

Two contributing factors will give rise to these rainfall amounts. There’ll be an initial band of heavy rain moving northwards on Thursday night, only to be followed by heavy, thundery downpours during Friday and Saturday.

The Environment Agency issued their three day flood risk forecast earlier which highlighted a low risk of river and surface water flooding across a large swathe of Wales as well as northern and western parts of England.

And it won’t just be heavy rain affecting the UK during the coming days. It’ll also turn windy for a time, with gales possible for coasts and hills – especially in the west.

Don’t forget you can get the latest forecast on the Channel 4 Weather website and the latest flood warnings are available from the Environment Agency.

If you have any reports, pictures or videos of bad weather or flooding, then please get in touch with me on Twitter – @liamdutton

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