10 Nov 2014

Heavy rain brings flood risk this week

Low pressure is going to be driving our weather this week, bringing heavy rain and a risk of flooding to southern and western parts of the UK.

After a balmy October, with temperatures resembling late summer rather than early winter, the weather has finally aligned with what it should be doing at this time of year.

So far, November has delivered weather more akin to autumn, with spells of wind and rain, punctuated by sunnier days and frosty nights.


If you’ve been following my blog during the past week, you’ll know that I recently wrote about hints of a change in our weather from mid-month onwards, with blocking high pressure and something colder possible.

Ironically, it’s the process of the change towards blocking high pressure and colder weather that is going to lead to rainfall amounts building up this week, giving a risk of flooding – especially for southern and western parts of the UK.

Slow-moving weather fronts

Normally in autumn, low pressure systems sweep from west to east, driven by the mid-latitude jet stream.

This often leads to a spell of heavy rain and brisk winds, followed by a drier, brighter and more settled interlude.

However, to the north and east of the UK this week, high pressure is building, which is acting as an atmospheric wall, impeding the progress of low pressure systems rolling in off the Atlantic Ocean.

chart_atlantic12thNov_MO_wpMet Office weather chart showing low pressure over UK and high pressure to north

So, rather than sweeping through, weather fronts are becoming slow-moving, sitting over the similar places for prolonged periods of time.

From later on Monday until early on Wednesday, this will be the case across south west England, south Wales, resulting in spells of heavy rain and brisk winds affecting some places for around 36 hours.

Heavy rain and flood risk

The Met Office and the Environment Agency have highlighted that as a result of the heavy rain expected, there’s a low risk of some localised surface water flooding between now and Wednesday across south west England and south Wales.

ea_3day10thNov_wpOnce the rain clears through, there’ll be a temporary respite, before more heavy rain sweeps in during Thursday and Friday.

By this point, with a lot of rain having already fallen in the first half of the week, more rain could result in the risk of some river flooding locally – again for south west England and south Wales.

Looking even further ahead, similar concerns will remain into early next week too, with further slow-moving bands of rain expected.

When is it going to get colder?

There are still consistent signals from the weather computer models that around 18-20 November, high pressure will build across the UK from the north and east.

This would lead to a quieter spell of weather for much of the UK, with frost and fog likely to become prevalent.

At the moment, temperatures are expected to drop a little, but nothing exceptional, making talk of snow at this stage premature.

Nevertheless, if the high pressure holds, it will have the potential to deliver a shot of cold air that will remind us that winter is definitely just around the corner.

Don’t forget you can get the latest forecast on the Channel 4 Weather website, as well as the latest flood warnings for England and Wales on the Channel 4 News live flood warning map. I’ll also be posting regular updates on Twitter – @liamdutton

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