Met Éireann has issued a status yellow snow and ice warning for all of Ireland, which came into force at 10pm on Wednesday.
The forecaster said there would be blustery conditions and squally showers of hail, sleet and snow.
This is expected to create icy stretches on untreated surfaces which the warning states will lead to hazardous driving conditions on Wednesday night and Thursday morning.
“Some thunder and lightning is expected too,” it said.
The warning will be in place until noon on Thursday.
Meanwhile, the UK Met Office has issued a status yellow snow warning for counties Antrim, Fermanagh, Tyrone and Derry.
“Frequent heavy snow showers are expected, along with very gusty winds and a chance of frequent lightning affecting some places,” it said.
The warning came into effect at 5pm on Wednesday and remains until 8pm on Thursday.
The weather advice comes as some areas are still attempting to recover from the effects of storms Dudley, Eunice and Franklin, which have hit Ireland since last Wednesday.
Forecast
Met Éireann had said Wednesday would feature sunny spells and scattered blustery showers before nightfall with rain in the northwest gradually extending to all other areas and turning heavy in places.
Wednesday night was expected to be “chilly with a scattering of snow, sleet and rain showers”, according to the national forecaster.
There is some chance of thunderstorms with local hail overnight, and lowest temperatures will be between -2 to +1 degrees. Some frost and ice will set in, especially in sheltered areas.
Thursday
It will be cold and very windy on Thursday with strong to gale force, gusty west to northwest winds bringing in sunny spells and further scattered wintry showers, said Met Éireann.
A scattering of snow showers and icy stretches during the morning will lead to very poor conditions in parts. Some thundery showers and hail too, especially in the west and north. Highest temperatures of +3 to +7 degrees are expected, coldest in the north, with an added wind chill factor.
The forecast for Friday is for drier conditions extending into Saturday before turning wet for a time later over the weekend.