Frost and fog to start December – but probably no snow

With November about to draw to a close, the arrival of December marks the start of meteorological winter, with thoughts not only of Christmas in our minds, but also the prospect of snow.

November has been another month that has delivered above average rainfall and temperatures across the UK, but what will December offer us?

The driver of our weather, the jet stream, has been throwing areas of low pressure at us during the past few weeks, bringing rain and brisk winds, as well as some localised flooding.

However, the jet stream is about to change position, causing high pressure to take control for the start of December.

A splitting jet stream

During much of November, the jet stream has taken a path over or close to us, leading to low pressure systems arriving.

This is about to change, with the jet stream splitting into two branches to the west of the UK.

One branch is going to head north towards Iceland and Scandinavia, with another branch diving southwards towards Iberia and the Mediterranean.

This will allow high pressure to build close to or over the UK, leading to a change to quieter, more settled weather than what we’ve been used to lately.

Colder with frost and fog

As high pressure builds into the first part of December, most of us will swap cloud, wind and rain for bright skies, frost and fog.

But even though high pressure is going to cause the weather to settle down, it could provide a bit of a headache for us meteorological folk.

Sometimes, cloud and moisture can get stuck under an area of high pressure – something that weather computer models don’t handle very well.

This means that it can be hard to predict amounts of cloud and therefore sunshine. So, what originally may be billed as early winter sunshine can turn into days of gloom.

Mediterranean soaker

Whilst high pressure will deliver us something calmer and more settled for the start of December, the low pressure systems that we normally see will be steered further southwards.

This will see cloud, wind and rain directed towards Iberia, north west Africa and the Mediterranean.

These areas have already had quite a bit of rain during the past month, so more rain will only exacerbate the risk of flooding and disruption in the next week to 10 days.

On a positive note, the presence of moisture over southern parts of Europe will give the prospect of some welcome snow over the Alps.

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