MODELLING SUGGESTS THE same weather event responsible for the 2018 cold spell will happen again over the coming days – but it’s not yet guaranteed to be an extreme weather event in Ireland.
It also won’t bring any instant change to our weather. The impact, if any, can take some time to become apparent.
A combination of the Beast from the East and Storm Emma in late February 2018 caused cold easterly winds and widespread snow across Ireland, prompting Met Éireann to issue a Status Red weather warning for the entire country.
Temperatures approaching -10 degrees Celsius and snow depths of more than 60cm were recorded in some areas as the two weather events combined.
However, an event known as sudden stratospheric warming (SSW) took place in the weeks running up to this at the start of February 2018.
This is where the stratosphere layer of Earth’s atmosphere – located from around 10km to 50km above the planet’s surface – undergoes, as the name suggests, a sudden warming.
The same happened before The Big Freeze in 2010.
Analysis of the 2018 cold snap by Met Éireann found that SSW ‘led directly’ to the cold weather later in the month.
Others have made similar findings. Research by the University of Reading described SSW as the ‘trigger’ for the Beast from the East.
Met Éireann’s climate unit tweeted last night that there is now ‘cross-model agreement’ – meaning several weather modelling calculations made the same prediction – for a major SSW event within the next week.
While the forecaster has shared this modelling prediction, it is too early to appear in any formal forecasts. The outlook is that cold conditions, with daytime temperatures struggling to get above freezing and longer spells of sleet and snow possible, are expected to continue right through to next weekend at least.
Speaking to The Telegraph, Grahame Madge from the United Kingdom’s Met Office said the long-term outlook is not yet clear.
“Two out of three SSW events result in very cold episodes, but one in three has little impact at all,” he said.
Alan O’Reilly of Carlow Weather highlighted a similar trend: SSW does not always equal cold weather for Ireland, and extreme cold weather is not always preceded by SSW.
He told The Hard Shoulder on Newstalk yesterday that it could be the end of the month before any potential impact is felt.
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