BBC monthly outlook
Summary
Unsettled at first but turning drier and colder.
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Saturday 23 January – Sunday 31 January
Changeable pattern of cold snaps and mild spells.
This weekend, as Storm Christoph moves away in Scandinavia, a colder air mass will feed into the UK from the north. This will lead to some lighter winds and sunnier skies at times. But also bring temperatures below average throughout the country. Despite the sunshine in some places, a few weak low pressure systems this weekend will bring a risk of lowland snow to western and southern areas. There will also be a band of snow likely on Sunday moving through southern Wales and England.
For the first half of next week, the colder air mass will remain in place keeping things drier than normal and colder than normal. Some sharp frosts are likely, especially in Scotland. On Tuesday night and into Wednesday, the next low pressure system from the Atlantic will arrive bringing a band of rain spreading northwest across the UK into Wednesday afternoon. This will also bring some milder air from the sub-tropical Atlantic. So after a few colder days, temperatures are expected to recover around midweek. Through the end of the week and following weekend, the weather will continue to be warmer than normal for late-January. It will also be unsettled with some stronger winds at times.
There are some early signals for a potentially stormy weekend to close out January. There is still some uncertainty on the strength and timing of this low pressure system. This may stay out over the ocean. In short, it will be a quite changeable week with a cold, mostly dry. It will be a frosty start and mild, wet, and windy finish.
Monday 1 February – Sunday 7 February
Unsettled and changeable weather continues.
For the first week of February, we don't expect too much to change in the weather pattern from late-January. The low pressure track will continue to send Atlantic weather systems into the UK from the west and southwest making for a changeable week. There will be mild, wet, and windy spells mixed with drier cold snaps with sharp frosts. There will also be a slight chance of some wintry weather even to low levels at times. High pressure is expected to gradually build over Greenland in early February.
This will tend to push the low pressure track further south. This will be a slow process and likely not happen until a bit later in the month. However, there will be plenty of cold air nearby to the north and northeast that will become increasingly widespread. The cold snaps in early-February may tend to feel a bit colder than the ones in late-January. This may last for a few more days. As the low pressure systems move in from the sub-tropical Atlantic, they will be able to tap into some warmer air to give them a bit more energy. There is a chance that we can see another storm push through similar to Storm Christoph. Confidence is pretty high overall for early February for Europe. But for the UK, confidence is a bit lower as we are on the boundary between two different air masses. The difference between the colder and warmer air masses is around 15 Celsius! So minor shifts could lead to some large swings in the expected temperature for a given day.
Monday 8 February – Sunday 21 February
Gradually turning drier but colder.
As we head into the second and third weeks of February, we will likely see a gradual pattern shift away from the more unsettled weather of January to a drier, colder picture. This is because the high pressure system in Greenland from early February will strengthen enough to eventually push lows into South Europe. Therefore, Spain and Italy will get all the wet and windy weather. For the UK, the colder air mass will move in from the north and bring temperatures consistently below average.
This will also be a drier air mass, so rain (or snow rather) is not expected to be as frequent. This will be a gradual change though; likely taking place over several days through mid-February.
There will still be some wet, windy, and mild days at first. By the third week of February and beyond, it will likely be largely dry but cold. The colder air mass will help create some sharp frosts overnight for much of the country. Despite the days growing longer as we head to the end of meteorological winter, late-February could well end up being colder than late-January as air masses continue to shift around. Confidence for middle and late February's weather is still low. There is a lot riding on the exact strength of the Greenland High pressure, which computer models are currently doing a pretty poor job of forecasting.
Further ahead
We will closely monitor the Greenland High's development through late-January and see just how tenacious it might be through February - and how long this cold may linger.
https://www.bbc.co.uk/weather/outlook