Batten down the tulips, a ‘sudden stratospheric warming’ may bring snow
Weather phenomenon was last present during December 2010 big freeze
A sudden stratospheric warming has taken place
The recent spring weather looks like a brief respite with the possibility of snow and ice returning next week.
Met Éireann said it is expecting much colder weather to set in from Sunday night while forecasters in the UK and elewhere say the cold snap next week will be caused by what is known as a “sudden stratospheric warming” in the polar vortex.
The polar vortex is a current of air 50 kilometres above the North Pole. It keeps the jet stream in place which drives the relatively mild winters that Ireland and Britain experience as it funnels in mild, wet weather from the Atlantic.
Meteorologists are now anticipating a weakening of the polar vortex which will in turn bring in cold air from Siberia across western Europe next week.
UK Met Office spokesman Oli Claydon said: “There is a very big, very cold pool of air that circulates around the North Pole — sudden stratospheric warming, as it says on the tin, is when the stratosphere suddenly warms,” he said.
“Last week we saw that take place — a sudden jump of around 50 Celsius — so that can disturb the way that cold pool of air moves around the North Pole very high up.
“That can lead in around 70 per cent of instances to it impacting the drivers that affect our weather in northern Europe as well. So what we are seeing in this case is it disturbing the jet stream and weakening the jet stream.”
The last “sudden stratospheric warming” was present in 2010 which brought the coldest December on record for most parts of Ireland with low temperatures of minus 17.5 degrees in places.
While Met Éireann is expecting much colder weather to set in from Sunday the cold snap is not expected to be on the same scale as December 2010.
Day time temperatures on Monday will be just three degrees with lows of minus 5 at night.
Forecaster Liz Gavin said there is an “increased chance of wintery precipitation” next week especially in eastern areas. This could fall as snow or sleet.
She added though that the cold snap may be relatively short lived with milder conditions setting in from the middle of next week.
Met Éireann’s long-range forecast for Monday and Tuesday says: “Very cold for the time of year with daytime temperatures in the low single figures inland, and around 5 or 6 degrees on coasts. There is an increased threat of wintry precipitation in the form of showers. Frosty nights with sub-zero temperatures will continue.”