GFS is predicting a Sudden Stratospheric Warming (SSW) event for early December and it could herald a bitterly cold spell of weather.
So whilst its unusual to see a SSW this early in the Season, The question is, How might it affect the weather over the coming weeks/months? And what are do all these words SSW? Polar Vortex? Stratosphere? mean to us…
Firstly the Polar Vortex is a column of air that circulates the North Pole throughout Winter. Its situated in the Stratosphere, A layer of the atmosphere that sits above the Troposphere (Where our weather forms).
A colder, more powerful Vortex is often associated with a powerful Jet Stream, which often brings mild, wet and windy weather across the UK and Europe. However, A disruption to the Vortex can trickle down into the Troposphere, creating a weaker and fragmented Jet Stream flow (Meridional flow) which can bring colder conditions across the UK and Europe. A significant SSW could go even further and see a complete reverse of the typical Zonal westerly wind direction and lead to the UK being chilled by a Bitter Easterly which can often last for a number of weeks!
SSW’s are signals that the Polar Vortex is under attack and might begin to break/slow down. If the warming penetrates the core, A breakdown of the Polar Vortex is inevitable, which can have big impacts on the weather right across the Northern Hemisphere.
Now whilst its only a forecast of an SSW event its to be taken with a degree of caution and also worth remembering not all SSW events lead to the UK being locked in the freezer, After all even when the Easterly wind blows the UK & Ireland are the last in line for the cold to reach and therefor need the pattern to remain in place for longer.
Despite this its certainly worth keeping an eye on as it could see the UK facing, Dare I say it? A 2010 type December!