Strong arctic front - dropping temperatures and snow for the Montreal region

Snowfall predictions have been difficult all season for the Montreal area, with highly variable temperatures across the region and challenging storm tracks. Monday was no different, as an over performing clipper system brought 7cm to the region. The forecast was for 1-2cm. Another challenging forecast lies ahead for southern Quebec over the next 24 hours. (Valley Weather Photo)

Yellow Snowfall Warning in effect for Southern Quebec.

It is a spring-like 5C (41F) in Montreal on Wednesday morning, along with light rain and massive potholes. A mix of rain and snow fell overnight, with only minor accumulations. We can expect a drastic change in our weather over the next 24 hours, as a strong cold front sinks southeast across Ontario and Quebec. Very cold air will surge in behind that front along with rain changing to snow.

Low pressure is forecast to develop along the sagging cold front late today in western New York. That storm will move northeast into northern Vermont on Thursday and Atlantic Canada by Friday. North and west of the track snow will develop. Models are all over the place with accumulations as this is a rather complex set up. The low end predictions are for 5cm or less, while some higher end estimates are for up to 30cm. All depends on the timing of the cold air arrival and development and track of the storm system.

Most forecasters are going right up the middle with snowfall estimates, so we can expect rain to change to snow after midnight in Montreal. The snow may become heavy at times through Thursday, as the low pressure strengthens and passes to our south. For Montreal and most of southern Quebec, a general 10-15cm is expected. More may fall just north of the city and across upstate New York, with less in the Ottawa Valley and Vermont.

Temperatures will be warm on Wednesday, around 5C (41F), dropping quickly behind the cold front overnight to -5C (23F) by morning. Temperatures will continue to fall Thursday into Friday morning, with morning lows near -12C (10F). Friday will remain blustery and cold, with flurries and steady temperatures.

Winds will be gusty from the southwest Wednesday between 20-40km/h, backing to the west and northwest after midnight, up to 30km/h.

Expect very challenging driving conditions across eastern Ontario and southern Quebec for the morning commute on Thursday, with falling snow, dropping temperatures and snow-packed icy roads.