Environment Canada upgraded its winter storm watch to a snowfall warning for Winnipeg and the Portage la Prairie region as darkness fell Sunday.
"The worst conditions are expected in the Portage la Prairie region where we expect 10 to 15 cm of snow tonight followed by strong north winds, blowing snow and poor visibilities Monday," the snowfall warning said.
Overnight Sunday and most of the day Monday are expected to be messy, particularly on highways.
"Weather conditions will improve from the west late Monday afternoon and evening," Environment Canada said.
Temperatures are expected to hold steady, with lows overnight of -10 C dropping slightly for a high Monday of -11 C. With wind chills, it will feel like -27.
Overnight, Winnipeg can expect five to 10 cm of snow with wind from the southeast at 30 kilometres an hour gusting to 50 and becoming light after midnight.
On Monday, the city can expect another two to four cm of snow, with wind from the north at 40 kilometres an hour gusting to 60.
Southwestern Manitoba can expect the first hit, with snowfall amounts of 10 to 15 cm tonight and Monday morning. Amounts could exceed 25 cm over southwestern Manitoba before the storm moves off, with the heaviest amounts north of the Trans-Canada Highway.
Some areas in the Dauphin and Minnedosa regions near Riding Mountain National Park may see as much as 30 to 40 cm of snow.
Over southeastern Manitoba, 5 to 15 cm of snow is expected with this system.
In addition to the snow, gusty northwesterly winds will create reduced visibilities in blowing snow on Monday.
A low-pressure system currently located in northwestern South Dakota is tracking eastward into Minnesota. Weather conditions are expected to improve from the west late Monday afternoon and evening.