Updated: 12.20pm
Met Éireann warned of "treacherous" conditions on Thursday as the country was placed under a yellow warning for ice.
The ice warning began at midnight and lasted midday on Thursday, while a second yellow warning for low temperatures and ice begins at 10pm, lasting until 10am on Friday.
The forecaster issued a winter weather advisory on Sunday, lasting until Monday morning, as an Arctic airmass sets in "bringing sharp to severe frosts, and ice or black ice on roads and footpaths".
However, climate scientist Cathal Nolan told Newstalk's Pat Kenny Show that the current cold spell may last longer than originally anticipated.
He said temperatures are likely to remain low until Saturday, December 17th, with the possibility of heavy snow after that as "warmer, moister air" arrives.
Mr Nolan also warned that nighttime temperatures could fall as low as -6 degrees in parts of the country over the coming days, while daytime temperatures are not likely to rise far above freezing.
Treacherous this morning with ice & black ice, as well as pockets of freezing fog. ⚠️ 🌫️
Scattered wintry showers will sink southwards with sunny spells following. 🌨️
Very cold with highs of 1 to 5°C in mostly light northerly breezes. 🍃 pic.twitter.com/IgqXLIeH3j— Met Éireann (@MetEireann) December 8, 2022
Ice, black ice and pockets of freezing fog were noted across the country on Thursday morning, leading to "hazardous travel conditions", Met Éireann said.
The forecaster added the day will be very cold, with highs of just 1-5 degrees.
The UK Met Office has issued similar ice warnings for the North, adding that "some disruption is likely due to icy surfaces".
Antrim, Derry, Down, Tyrone and Fermanagh were placed under a yellow warning for ice at 5pm on Wednesday. The alert is due to expire at 6pm on Thursday.
Later, the same five counties will again be placed under a yellow ice warning, from 4pm on Thursday to midday on Friday.
An icy start to Thursday with black ice & patches of freezing fog leading to hazardous travel conditions. ⚠️🚗 🚴♂️ 🚶♀️
Further well scattered wintry showers will occur in the morning with a light dusting of snow on some lower levels. 🌨️ ❄️https://t.co/l8JdKfwZt9 pic.twitter.com/hwelldv3jl— Met Éireann (@MetEireann) December 7, 2022
"Further well scattered wintry showers will occur in the morning with a light dusting of snow on some lower levels."
Speaking to RTÉ Radio's Morning Ireland on Thursday morning, meteorologist Siobhán Ryan urged motorists to take extra caution due to widespread black ice on the roads.
Black ice is invisible to the naked eye and results in treacherous road conditions, she said.
Ms Ryan added that it is going to be bitterly cold for the foreseeable future, well into next week. For Thursday, there is a threat of sleet and snow in the east with temperatures well below average throughout the country, she said.
The weekend will bring "a new set of problems", Ms Ryan warned, with freezing fog predicted for Saturday and Sunday resulting in impaired visibility and dangerous driving conditions.
