Many in the media have been reporting that the UK is heading for a bitter cold spell with large amounts of snow and FREEZING days with temperatures failing to hit positive figures.
So why have they been talking about this recently?
The answer lies with the Stratosphere.
From roughly the 23rd of December the Stratosphere has seen a significant rise in temperatures and this warming is expected to last into January.
This can lead to wobble of the usual Zonal winds pushing West to East and instead we see a wavy pattern. This can then allow High pressure to build at higher latitudes which increases the chance of a cold North or Easterly air flow over the UK.
All of this can take 2/3 weeks from the date of the Sudden Stratospheric Warming event to influence the weather we see and thus the Met Office is predicting a colder spell from the 3rd week in January.
However whilst this can be the outcome and the likelihood of cold weather is increased it by no means guarentees that it will happen and as of now no immediate threat is being predicted by the weather models.
The warnings keep on coming as the first significant wintry spell sets it sights on the UK.
Before we get into the detail its worth baring in mind that whilst there is a severe spell of weather expected the duration is expected to be quite short with the main timeframe for severe conditions from Saturday afternoon through till 06:00 Sunday with a return to average temperatures on Monday.
As you can there is alot to contend with over the 18 hour period from midday on Saturday. Even before this period begins areas outside of the areas shaded red may well see some wet snow falling for a short period of time however accumulations are unlikely.
As the bulk of the precipitation bumps into the cold air anywhere from the North Midlands Northwards need to be prepared for snow or freezing rain. Initially snow is expected but as the weather fronts move across the UK it is likely a warm layer will melt the snow as it falls however temperatures at ground level may still be at or below freezing turning this super cooled rain immediately to ice upon impact.
This phenomenon is quite rare in the UK however it can be lethal for those who are braving the elements. Black ice will form readily and trees and powerlines can be brought down under the weight of the ice. The latter may not take place due to the relatively short period of time freezing rain is expected, However slippery surfaces are almost assured so it may be worth getting out and about early if you are still looking for those Christmas presents.
Another hazard will be for any of the high travel routes, The heavy snow in these areas will be accompanied by strong winds gusting up to 60MPH with a risk of Blizzard conditions so expect some road closures.
As for those outside of the areas shaded in red Saturday will be a blustery and wet day from around 3pm onwards before the rain clears away during the evening. This will then be followed up by a much calmer, drier day Sunday.
Winter has finally arrived this week with a particularly cold day expected across the UK on friday. Daytime maximums will struggle to get much above 2-4c for many of us with a widespread sharp frost expected Friday evening.
On Saturday a weather system off the Atlantic will attempt to shunt the cold air to our East. Whilst eventually this mild air will sweep right across the UK there is expected to be a spell of Heavy snowfall.
The Met Office warning issued today covers the following areas (Central Tayside & Fife, East Midlands, Grampian Highlands & Eilean Siar, North East England, North West England, SW Scotland, Lothian Borders, Strathclyde, Yorkshire & Humber) And warns of 2-5CM of snow for low levels and 10-20cms above 2-300M.