Despite apocalyptic warnings of the coldest ever December issued by the Daily Mirror, December turned out to be a mild month in the UK and the new year has started off in much the same fashion. In fact, the Highlands of Scotland, a place associated with some of the coldest temperatures across the UK in wintertime, recorded a new record high of of 18.7C on 28 December at Achfary, warmer than most of Europe!
Why is the weather mild?
Usually in winter cold winter weather comes straight down from the north, bringing Arctic sub zero temperatures in its wake. However, during December we saw a lot of the weather that forms towards the west over the Atlantic come over Britain, which explains much of the extraordinary level of rainfall that we've seen. This is also partially responsible for the unseasonal highs, as something called the Foehn Effect came into play.
What is the Foehn Effect?
The Foehn Effect occurs when moisture-laden and high humidity air gets pushed over high ground by strong winds. As the air rises, it cools and condenses, forming cloud and rain. The remaining dry air travels down the other side of the mountain, picking up heat as it goes and resulting in higher temperatures at ground level. In the UK, this effect is commonly seen in eastern Scotland, north-east Wales and north-east England.
What is the winter outlook?
Although we're in a warm spell at the turn of the year, longterm forecasts still suggest that we could be in for a cold spell during February and possibly March. The origin of this forecast is a paper put out by University College London at the at the end of August 2019, which predicted that temperatures will be colder than normal during January-February 2020. Their data points to a higher than normal likelihood that the North Atlantic Oscillation (NAO) will be negative, and that the central England temperature (CET) will be colder than normal for January-February 2020. Specifically, their weather data analysis points to an 87% probability that the NAO will be less than the 1981-2010 mean, and a 65% probability that the CET will be the colder than the 1981-2010 mean. To back up their data, they point to 1953-2019 weather data analysis, which shows that in nine of the ten years where these predictor fields had the same sign and similar magnitude to that in summer 2019 were followed in January-February by a negative NAO and by a CET "colder than the climatology".
Snow next week?
Looking through the weather data for the next two or so weeks, our weather forecasters Metdesk are not predicting any avalanches or apocalypses, but next week should have some snow across the country if trends remain as they are. We're not talking a major event yet, but more a bit of a dusting across the higher parts of the country as would normally be expected at this time of year.
What if it gets colder?
Nobody obviously actually knows for certain if the rest of this winter is set to be especially cold or not, although the indicators would tend towards a very cold early part of the year. Slips, trips and falls in car parks and on footpaths are common in the wintry months, and should the weather deteriorate even further, you may find that business and operations grind to a halt if you're not prepared for inclement weather. As a business, school, facility or factory, you can cover yourself with a fixed budget for the entire season by speaking to one of the experts at GRITIT. We'll cover any claims against you and we'll always be there to grit your facility and clear away the snow.