Here’s why the ‘Beast from the East’ is going to make it so cold in Ireland this week

When a weather warning is issued for an entire week, you know it’s a big deal.

Given our obsession with the weather in this country, there’s a good chance you’ve heard that it’s going to be mighty cold throughout Ireland for the foreseeable future. “Exceptionally cold”, in fact. So cold, that at midday on Friday, Met Éireann issued a status yellow weather warning that will last until midday next Friday, 2 March, with significant wind chill, severe frosts and disruptive snow showers forecast for the next seven days. This type of weather is rare enough in Ireland, particularly at this time of year, and Met Éireann have attributed the conditions, in part at least, to something called a Sudden Stratospheric Warming (SSW). Prepare for a little bit of science... According to Met Éireann, a Sudden Stratospheric Warming of the atmosphere refers to a rapid jump in temperatures in the stratosphere (up to approximately 50 degrees Celsius in a couple of days), which can then lead to the onset of cold weather in winter for the mid-latitudes (including Ireland amongst other countries). The SSW is explained in greater detail here, but, basically, a ‘wobbling’ of the jet stream can eventually alter weather patterns in the northern hemisphere by displacing a rotation of very cold air around the north pole called the tropospheric polar vortex. This, in turn, pushes the jet stream further south, leading to the development of a blocking high-pressure system at higher latitudes, which can remain in place for several days or even weeks. If these blocking highs become established over Scandinavia or Greenland, it can lead to bitterly cold air from eastern Europe/Russia – the so called ‘Beast from the East’ – pushing in over Ireland. A SSW event in January 2013, for example, led to a very cold month of March and some significant snowfall accumulations. All in all, that’s why it’s going to be bloody freezing at least until Friday and possibly even beyond that. Wrap up well, folks.