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In the end, a bitterly cold easterly setup is now highly unlikely to reach our shores after what has seemed like a marathon period of weather watching and waiting for an anticipated mid-February cold spell.
What had looked like a Polar Vortex Split and possible major Sudden Stratospheric Warming (SSW) at the turn of the month was watered down into a displacement of cold air over the Arctic into the mid-latitudes and eventually a guessing game for which regions would be plunged into a deep cold spell. Long range weather models consistently pointed to there being a moderate chance of much colder weather impacting Ireland and Britain around or beyond mid-February. It is worth pointing out that the Beast from the East of 2018 was an exceptional event and there was never strong support for a repeat event, despite what the online news sites reported on a daily basis.
In the end, an Atlantic low pressure system disrupted any path to a cold spell. It likely would have been a different story if the low were further south, but its northerly position has disrupted the amplification of heights to our north and east.
Key building blocks for a cold spell are falling into place including a Scandinavian high, Greenland high and a displacement resulting in deep pool of cold air over the continent primed to push west. Furthermore, the surface temperature is already low here following a week of below average temperatures. As is the norm for a country placed on the edge of an ocean and whose climate is kept temperate by the Gulf Stream, Ireland needs a clean sweep of the key building blocks in place for a severe cold spell to materialize. There was one missing block that has compromised the foundations for any severe cold to take hold in Ireland. The Atlantic has delivered a December 2021 performance in defying the odds by bringing the Jenga tower of building blocks down.
In reality, the models have had such an outcome highlighted as a strong possibility for over a week. A return to milder and more unsettled weather ultimately became the form horse ever since the Sunday morning weather model runs.
As long as I have been weather watching, it never ceases to amaze me how strong the Atlantic influence is in situations like this where everything points to a colder solution. Even looking at the pressure charts tonight, a gambler who didn't have the luxury of knowing what the charts would produce in 5 days time would be hard pressed not to place money on a cold outcome. If weather was the leading focus of the gambling industry, the advice would be to never rule out the Atlantic irrespective of the odds.
The Atlantic is King when it comes to our weather. It rules our climate from one end of the year to the next by delivering us a year-round spring interpersed with fleeting glimpses of what other parts of the world call summer and winter. Chasing those glimpses is what makes weather watching in this country a rollercoaster.