10 Jan 2014

Winter lurks but may not pounce yet

A few days ago, I wrote a blog about hints that winter proper may be about to pounce on us next week, as the UK found itself caught in the middle of a battle between cold air to the east and mild air to the west.

At that point, it looked as if the weather computer models were favouring the colder air to win, with lower temperatures and snow a possibility.

However, I did point out that there was still some uncertainty and that the detail could change, which it indeed has.

wintersky_rainbow_g_wp

Temperatures now look likely to return to close to average, rather than anything notably cold, which does reduce the risk of snow.

Why such uncertainty?

In situations where cold and warm air collides, weather computer models can often struggle to grasp the fine detail as to precisely where the boundary of cold and warm air will lie.

This is particularly true when such changes are slow in comparison to the usual haste in which weather across the UK normally progresses.

One notable change has been the orientation of low pressure to the west of the UK early next week. Initially it stretched north west to south east, which would have favoured an eventual change to cold easterly winds and high pressure.

However, now it looks like the orientation of low pressure will be more north to south, favouring a less cold south to south easterly wind and high pressure staying to the east of the UK.

Rain and flood risk continues

welly_puddle_g_wpOne consequence of the subtle changes for next week is that weather fronts will now make greater progress across the UK than they would have if high pressure had become established.

This means that further bands of rain will move in off the Atlantic, bringing more wet weather at a time when it really isn’t needed, given that the ground is saturated and river levels are still high.

Whilst it is still a little early to be sure about which places will see more rain and exactly how much, it may be a case of having taken one step forward and two steps back.

Don’t forget, you can get the latest forecast on the Channel 4 Weather website. I’ll also be posting regular updates on Twitter – @liamdutton

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