As is often the case in winter, long range weather models maroon Ireland in a meteorological no man’s land, sitting between a mobile and milder Atlantic pattern and colder, more settled conditions to our east. This afternoon’s GEM output captures well the complexity of what may happen to our weather over the next 10 days.

There are three main forecast outcomes to consider.

First, Ireland could remain in a largely zonal Atlantic pattern, bringing spells of rain, occasional strong winds, and temperatures close to or slightly below average.

Second, the meeting point between higher pressure to our east and Atlantic low pressure systems could sit over Ireland. This would lead to mostly overcast but generally settled conditions, with slightly below average temperatures as colder air slowly feeds in from the east.

Third, an easterly airflow could become established, opening the door to a much colder pool of air over Eurasia that may track westwards over Ireland during the final 7 to 9 days of the month.

A number of factors will decide which outcome prevails. One of the most important is the extent of blocking that develops. For example, can high pressure over Scandinavia extend far enough west to link up with high pressure near Greenland? If so, this would divert Atlantic systems and the jet stream away from Ireland and allow winds to turn east or northeast.

On the other hand, there is the familiar winter issue of Arctic air plunging into North America. This often energises the jet stream and drives low pressure systems quickly across the Atlantic towards Ireland.

At present, model output suggests that both of these influences are at play, which helps to explain the up and down nature of recent operational runs.

A change does appear to be under way. Large swings in model output usually point to an atmosphere in transition. For now, Ireland remaining in this meteorological no man’s land looks just as likely as a return to a fully mobile Atlantic pattern or a decisive move to a cold easterly setup. There is still a lot to be resolved in the days ahead.