You may have heard chatter online and in particularly on social media about the potential of a bitterly cold December on the way for Ireland and the UK. The truth is that we are a while off from being able to make a judgement call on such an outcome.

For anyone watching for signs of deeper cold in December, the baseline remains low. Out of 30 GEFS ensemble members, only one is offering a truly cold scenario, and that emerges only at the far end of the latest run. That tells you something about the level of uncertainty involved.

What is becoming clearer, however, is that the polar vortex is under pressure. A displacement or stretching of the vortex looks increasingly likely as we approach the end of the month, and the prospect of a technical Sudden Stratospheric Warming remains in play. Such events can weaken the polar region for two to three weeks afterwards, allowing colder air to spill south into the mid latitudes. But where that cold ultimately goes is still an open question.

Ireland’s own history with major SSW events is mixed. Only a small fraction of the roughly 25 major events over the past four decades have delivered severe cold here. The February 2018 event produced the memorable Beast from the East. A year later, a significant SSW left Ireland largely untouched, with conditions staying mild through the remainder of the season. Another in January 2021 did bring colder weather, but nothing like the extremes of 2018.

By early next week, the models should begin to resolve the first hints of what mid December might hold. Expect the usual rollercoaster of outputs, with some runs showing exceptional mildness, others will lean towards sharp cold. That volatility is typical when the atmosphere is in flux.

For now, patience remains the sensible stance. The much-discussed cold start to winter may yet materialise or, as past years have shown, fade just as quickly. In Ireland, winter reveals its hand in its own time, not in the fevered and increasingly combative and sensational corners of social media and online clickbait news sites.

In the meantime, the current cold snap will slowly moderate through the second half of Friday as rain and slightly milder conditions return. Some snow has fallen on the hills and mountains of Ulster as these photographs from the Sperrins show. Temperatures will drop to as low as -4c tonight with a low temperature warning in place for 10 counties.