The Met Office warning means that severe weather is possible and that people should plan ahead with a view to possible travel delays and disruption of day to day activities.
“On Tuesday, the further west you go the more likely you are to see snow showers,” he said.
There could be some milder air on Wednesday night into Thursday but this is not definite.
For the rest of the week, although there may be some partial thawing during the day in the sun, there is the possibility of it refreezing during the night.
However, with temperatures forecast to remain between -1 to 5C for the rest of the week, melting and refreezing snow could cause potential hazards on untreated footpaths and roads until the weekend – and possibly beyond.
“To begin with, Monday will see showers falling as rain and sleet on higher ground. In the afternoon it will become colder, falling as snow on hills and sleet on higher ground.
A forecaster told the News Letter: “Monday and Tuesday will see colder air coming in from the polar regions, from the north west.