Forecasters are warning of risks of travel disruption and difficult driving conditions with overnight snowfalls being followed by gale force winds as a "vigorous" low pressure system sweeps across Northern Ireland.
Overnight, showers were forecast to turn to snow, continuing into this morning particularly in northern areas. Accumulations to 2-5cm were predicted on ground above 200m, with more than 10cm possible on higher ground.
There will be a significant wind chill making it feel much colder.
The Met Office has issued a series of severe weather warnings and said this will be followed by a vigorous area of low pressure which is expected to sweep across Northern Ireland later today, bringing a swathe of south-westerly gales.
The warning predicted a risk of disruption to transport and possibly power supplies, with large waves affecting some UK coastlines.
Forecasters MeteoGroup said the centre of the low pressure system is expected to move across Northern Ireland, making it tricky to predict when the gales will be at their height.
The centre of the low is expected to bring a lull in the high winds, with strong winds expected around midday and again late afternoon.
"We could see gusts of 50-60mph and it could potentially be a little bit stronger than that in places," MeteoGroup forecaster Gareth Harvey said.
"We're looking at probably quite a dry start, then rain and possibly some sleet for a time coming in from the south west.
"We could get some very heavy rain for a time, becoming more showery in the afternoon and again some heavy periods of rain are likely to be mixed in with that. There's a chance in the evening of wintry showers developing."
Wintry showers could continue into tomorrow and Thursday, although it is expected to be drier on Thursday and Friday.
"Into the weekend, there's a chance of more strong winds and outbreaks of rain," Mr Harvey added.
Roads Service warned that temperatures are forecast to drop below freezing overnight with a risk of snow and ice on the roads.
"Road users are advised to exercise caution when travelling, particularly on untreated roads," a spokesman said.
Yesterday photographs were coming in of snow blanketing northerly areas such as Coleraine, Derry and Strabane.
The Met Office said more showers bringing hail and sleet are likely throughout the rest of the week.
Temperatures should hover just above freezing, but will feel much colder – more like minus 4/5C.