13 Apr 2012

A wet and windy week lies ahead

The week just gone has been dominated by low pressure that brought most places a spell of rain on Easter Monday and then parked itself in the North Sea bringing heavy, thundery showers thereafter.

Whilst amounts of rain have been highly variable, as is always the case with showers, the thirst of the dry ground has been quenched slightly, although nowhere near enough to replenish the water resources of the drought-hit areas.

I mentioned at the end of March that April looked to be a very different month in terms of what the weather had to offer. The main signal was for a cool and unsettled theme, with showers or longer spells of rain and winds often from a northerly quarter. So far this month, it has certainly proven to be the case.

Next week will see the weather continue in a similar vain. An active jet stream will extend across the Atlantic Ocean, acting as a conveyor belt and driving areas of low pressure towards the UK.

It will also have a trend to dip south of the UK, which will keep us in a region known as the left exit of the jet stream. These regions are characterised by lower pressure, more readily rising air and also air that spins around more – all characteristics that contribute to an unsettled weather pattern.

The image below from NOAA shows the position and strength of the jet stream during the middle of next week. Note the blue coloured area snaking to the south and west of the UK showing the position of the jet stream. The darker blue indicates that it’s moving at around 130 knots – close to 150mph.

So what weather will this bring us? Well, it means another week dominated by low pressure. In fact it’s likely to feel quite autumnal with showers or longer spells of rain, often accompanied by brisk winds.

There’s a consistent signal from the weather computer models that all parts of the UK will see some notable rainfall. Eastern areas could see 15-30mm and western areas 20-50mm, with more possible across the hills and mountains.

It’s almost as if the weather has heard about the hosepipe ban and suddenly come to life, finally bringing rain – much needed rain to drought-hit areas. There’s no doubt that farmers, growers and water companies will welcome the rain-bearing clouds with open arms.

However, before the rain arrives later on Monday, the weather is winding down for the weekend. A brief ridge of high pressure will mean fewer showers on Saturday, mainly dry weather on Sunday, accompanied by a chilly wind. There’ll also be widespread frosts for the next few nights.

Before I sign off, I’d just like to say a huge thank you for all the weather reports and pictures that I’ve had on Twitter during this week. They have been really useful and help the weather to come to life even more. As always, you can contact me anytime – @liamdutton

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