An urgent weather alert was issued by Met Eireann on Wednesday afternoon with hazardous conditions to hit Ireland.
A Status Orange rain warning for Carlow, Kilkenny, Wexford, Wicklow and Waterford is in place for five hours.
Valid from 3.35pm until 9pm on Wednesday, the alert says "heavy falls of rain will continue with surface flooding and poor driving conditions".
It follows an earlier Met Eireann warning which will impact almost all counties nationwide.
The national forecaster announced a Status Yellow low temperature/ice warning for 24 counties with severe" and "hazardous" conditions forecast.
The areas affected are: Carlow, Kildare, Kilkenny, Laois, Longford, Meath, Offaly, Westmeath, Wexford, Wicklow, Cavan, Donegal, Monaghan, Munster and Connacht.
It will be in effect for 12 hours from 10pm on Wednesday until 10am on Thursday.
Met Eireann says these counties could be hit by "hazardous conditions due to a widespread severe frost leading to ice on untreated surfaces".
As for the national outlook, rain, sleet and some snow locally over the eastern half of the country will gradually clear from the west on Wednesday afternoon.
A forecaster said: "Locally hazardous driving conditions are possible for a time where sleet or snow accumulates. Munster and south Leinster are most at risk for these conditions. Drier and brighter to the west.
"Cool over all though with afternoon highs of 5 to 9 degrees in the western parts, but struggling to get above 2 and 5 degrees in the east in mostly light to moderate northwesterly or variable winds.
"Tonight will be largely dry and clear, however, on eastern fringes cloud and outbreaks of rain will linger through the night keeping it a little milder there. Some areas may see patches of sleet and snow also but accumulations where they do occur, will generally be small.
"Cold with lowest temperatures of -3 to +3 degrees. Hazardous conditions can be expected due to a widespread severe frost away from eastern fringes, with ice on untreated surfaces. Some pockets of dense fog or freezing fog will also occur, in mainly light variable winds."
They continued for Thursday: "Any frost, ice and fog will clear tomorrow morning to leave a largely dry and bright morning with sunny spells. However, cloud will build in from the Atlantic through the afternoon and evening with some patchy drizzle at times, but it will remain dry and bright in the east until later in the day.
"Turning breezier through the day also as light to moderate southerly winds increase fresh to strong during the afternoon. Highest temperatures of 7 to 10 degrees.
"Becoming cloudy with rain spreading to most areas from the southwest overnight [on Thursday night], turning heavy at times. Quite breezy with moderate to fresh southeasterly winds and lowest temperatures of 4 to 8 degrees.
"A wet start [on Friday] with widespread rain turning heavy in places. Rain will slowly clear northeastwards through the day with sunny spells and widespread showers following from the southwest. The showers will be heavy or thundery with hail possible. Highest temperatures of 7 to 11 degrees in light to moderate southerly winds.
"Becoming largely dry [ on Friday night] with clear spells, though there will be scattered showers along Atlantic coasts. Lowest temperatures of -1 to +2 degrees with frost and some icy patches developing in places. Patchy mist and fog developing too in light winds."
