BBC Outlook.
Monday 11 February—Sunday 17 February
Becoming a little less mild
In our last update, we mentioned that there was a chance of some colder weather arriving around the middle of February. The reason for this was because we expected high pressure currently over the east and north-east of Europe to start to extend westwards towards the UK, with cooler easterly winds potentially reaching our shores. Whilst this scenario still looks possible, it now seems more likely a little later in the month, with high pressure and cold air slower to spread westwards.
However, we do think that after a relatively mild spell, it will become a little cooler towards the middle of the month. This is mainly due to an expected reduction in the broadly westerly winds coming in from the Atlantic. In this case, it would also become drier.
It should be stressed that there is quite a lot of uncertainty for this period of the February, as there is low confidence in the timing of the transition from unsettled westerlies to more of a blocked, settled pattern.
We could potentially see low pressure systems continuing to push in from the west, with the weather remaining unsettled, wet and windy but mild. There is only a small risk of anything substantially colder at this stage.
Monday 18 February—Sunday 3 March
Chance of colder weather setting in
It is likely that the final third of February will see a cold spell developing across the UK. This is most likely to be due to a 'blocked' pattern across northern Europe, this preventing our usual mild flow in from the Atlantic, with an increased chance of easterly or north-easterly winds developing. All areas of the country look colder than normal, and many areas will be drier and less windy than normal. There will be an enhanced risk of snow to lower levels and overnight frosts.
There is some uncertainty over the duration and magnitude of this cold spell, and it seems likely that it will be a relatively short spell of cold weather, with things perhaps returning to nearer normal for the start of March.
Whilst a spell of cold weather is the most likely story, there is an alternative scenario which suggests that we could see the Atlantic maintaining some influence on the weather. This would mean that it wouldn't be as widely cold - temperatures would be nearer normal - and there would be a reduced risk of snow. However, it would probably still be cooler than average for the time of year.
https://www.bbc.co.uk/weather/outlook