Cold snap next week to plunge country into sub-zero temperatures

A prolonged cold spell dubbed the “Norse Force” by Offaly meteorologist Cathal Nolan indicates a dramatic shift towards freezing cold temperatures next week.

According to the Ireland Weather Channel founder, both the GFS and ECMWF weather models indicate that temperatures would fall to values not seen since 2010, bringing about an icy regime that could last for some time.

“Recent cold temperatures, where it dropped to -8.2 degrees in Mullingar, have been the coldest weather we’ve seen since 2010,” begins Cathal Nolan, “but at the moment, given the weather models predictions, if this particular scenario plays out then this would overtake that and become the coldest spell since 2010,” he explains.

“It’s possible that it would be more like 2009 than 2010 in fact. 2010 was marked by significant snowfall, whereas 2009 stood out because of its freezing cold temperatures, and that’s what we’re more likely to see in the Midlands.

“Currently this particular cold spell looks like it will originate across the Arctic region and not from Siberia, meaning the primary focus of any wintry showers will be across the north and northwest of the country.

“The east, Midlands and south would remain largely dry but very, very cold for the most part.

“It all really depends on the wind direction. If we see the wind coming directly from the north and we don’t see any low pressure systems, we will stay predominantly dry in the Midlands, but it will still be very, very cold.

“If we see low pressure systems trying to push in from the south however, that will interact with the colder air across the country and then you have the risk of seeing some heavy snow.”

The shift in our weather towards negative values will commence from Monday next week, but it will be Wednesday before we start to feel its icy grip.

“It’s difficult to say exactly how long this cold spell of weather will last but at the moment all the conditions are present for a particularly prolonged period of cold weather,” Cathal continues, adding that there are two main factors leading up to a dramatic fall in temperatures.

“The first is the Sudden Stratospheric Warming event we witnessed over the last couple of weeks. This results in a massive change in the stratosphere over the Arctic region. This then filters down through the different layers of the atmosphere, and eventually reverses the typical directional flow of wind that we see.

“So instead of our usual west to east airflow that brings in our typical weather from the Atlantic, we’re going to see an east to west wind, which disrupts the flow of the jet stream, a buckling of the jetstream.

“As a result, we see much much colder air feeding down from the north as opposed to our typical mild south to southwesterly winds coming across the Atlantic at this time of the year.”

Blocking anticyclone

“The second reason then is we’re expecting to see a blocking anticyclone, characterised by high pressure across Greenland and possibly extending as far as Iceland,” Cathal adds.

“Again, this acts to keep those Atlantic weather rain-bearing systems at bay.

“Typically you experience north to northeasterly winds with this particular type of scenario, so as a result, we see much much colder than average conditions and of course the risk of wintry precipitation too.”

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