Met Éireann has warned that an "early cold snap" may lead to blizzards and freezing winds in parts of the north and west of the country over the coming days - with up to eight centimetres of snow expected to fall in some areas from noon today, writes John Downes.
It is also possible that the snow may spread to other areas by the weekend.
Issuing a severe weather warning yesterday, Met Éireann said counties Donegal, Mayo, Leitrim, Sligo and parts of Cavan are likely to experience the worst of the cold weather.
Over a 36-hour period starting from noon today, between three and eight centimetres of snow may fall in these areas.
"Strong to gale-force northerly winds will occur during the same period, giving blizzard conditions at times and causing some drifting," it said in a statement.
A spokesman said the snow is likely to be limited to these areas today and tomorrow. But the rest of the country is getting into a "cold spell" from today, meaning there is a possibility of snow showers spreading elsewhere by the weekend.
"It will feel quite raw. It has been cold in the last week and frosty, but this is a different regime," he told The Irish Times. "We don't want to panic people . . . but it will feel particularly cold because it is coming early. People will feel it.
"Certainly it is going to remain cold over the weekend and into the early part of next week. It is early days yet. . . but there is a risk of snow in other parts of the country over the weekend and into Saturday."
AA Roadwatch yesterday advised motorists travelling in the affected areas to take extra care.
Spokeswoman Emma Caulfield said that as the snow is not expected until noon today in the affected areas, it would be most likely to affect rush hour traffic this evening and tomorrow.
But she warned that the formation of black ice can present a significant danger in the case of severe snow.
"Snow closes roads down if it is really bad ... but our real fear is black ice, and snow falling over black ice," she said. "People should drive with extra care, and avoid sheltered areas, such as back roads, and reduce their speed."
AA Roadwatch has also received an "awful lot" of calls over recent days from road users complaining that motorists are forgetting to turn their fog lights off, Ms Caulfield said.
"A lot of people are putting on fog lights and not turning them off again," she said. "It has been very foggy the last few mornings, but leaving fog lights on is really blinding to other motorists."
A spokesman for bookmaker Boylesports told The Irish Times it was offering odds of 6 to 1 for a "white Christmas". Payouts are made if an inch or more of snow falls at Dublin airport on Christmas Day, he added.