Canada, US: Adverse winter weather conditions forecast across parts of southern Canada and the northern US through at least early March 25 /update 2

Adverse winter weather conditions are forecast across parts of southern Canada and the northern US through at least early March 25. A series of weather systems across the region over the coming days will bring heavy snowfall across parts of the affected area. A low-pressure system developing over the Great Lakes on March 22 will move eastward into northern New England and southern Quebec overnight March 22-23, bringing snowfall accumulations of 15-30 cm (6-12 inches) across parts of the affected regions through early March 24. Another system moving up from the southern US will generate heavy rainfall over parts of the Mid-Atlantic and urban Northeast US late March 22-23; rainfall totals of 2.5-7.5 cm (1-3 inches) are possible in affected areas. Perhaps the most potent system will move into the northern plains from the northwestern US on March 23 and is expected to develop into a significant winter storm as it tracks generally eastward towards the Midwest through March 24. Snowfall accumulations of more than 20 cm (8 inches) are expected from the North Dakota-South Dakota border eastward into Minnesota and northern Wisconsin late March 23-24. Strong winds associated with the storm system may combine with heavy snowfall to generate blizzard conditions across parts of the northern tier of the US late March 23-early March 25. Hazardous driving conditions are likely across the affected areas due to icy roads and reduced visibility caused by blowing snow.

As of early March 22, Environment Canada has issued red snowfall warnings (the highest level on a three-tier scale) for parts of southeastern Ontario, red winter storm warnings for parts of the Gaspe Peninsula in southeastern Quebec, and red wind warnings for Anticosti Island in Quebec. Special weather statements and weather advisories are in place across New Brunswick and parts of western Prince Edward Island, southern and south-central Ontario, and southern and southeastern Quebec.

The US National Weather Service (NWS) has issued winter storm warnings for much of Maine and parts of northern New York, central and northern Vermont, and central and northern New Hampshire. Winter storm watches have been issued for parts of central and eastern Montana, central and southern North Dakota, South Dakota, northern and western Minnesota, northwestern Wisconsin, southern New Hampshire, and northern and southern Maine. Winter weather advisories are in place for parts of northwestern Montana, central and southeastern Minnesota, northeastern Iowa, Wisconsin, far northern Illinois, central Michigan, Upstate New York, southern Vermont, western Massachusetts, and northwestern Connecticut. Flood watches are in place for northeastern coastal regions and adjacent inland areas from Delaware northward to Maine.

Officials will likely issue new alerts or update/rescind existing advisories as weather conditions change over the coming days.

Snow accumulations are likely across much of the affected area. Lesser snowfall totals are possible where sleet and freezing rain mix with snow. Heavy rainfall could trigger flooding in low-lying areas of the northeastern US. In addition to the heavy snow, strong wind gusts could lead to periods of blowing and drifting snow. Sporadic power outages may occur throughout the affected area.

The inclement weather will likely cause widespread ground and air transport disruptions across the affected areas. Traffic and commercial trucking delays are probable along regional highways. Dangerous and challenging driving conditions are also likely on secondary and rural roads as maintenance crews prioritize clearing major routes. Authorities will likely close stretches of highways if driving conditions become too hazardous. Gusty winds will threaten to topple high-profile vehicles throughout the affected areas. Mountain passes and tunnels will probably be closed as a precautionary measure during periods of intense snowfall. The disruptive weather will likely cause delays and cancellations at airports in the affected regions. Heavy, wet snow and strong winds could bring down power lines and trees with foliage.