Alpine weather forecast

All kinds of precip types

We’re in for quite the wintery mix of precipitation types over the next 36 hours! An incoming Colorado low is pushing a warm air mass over the Chic-Chocs which will cause snow to transition to ice pellets, freezing rain, and eventually rain. The snow that began just after midnight Sunday night will continue until about 11am Monday before becoming mixed with ice pellets (snow that has melted entirely and then refroze before reaching the ground). The mixture of snow and ice pellets is then forecast to continue until the evening when freezing rain will join the party before eventually transitioning to rain around midnight Tuesday. Strong southwest winds of 50-80 km/h will blow throughout the whole day Monday causing temperatures in the mountains to rise steadily from -6C in the morning to reach +1C Monday night. The good news is that the latest models have decreased the amount of freezing rain, now favoring more snow with 10-15 cm of snow mixed with ice pellets, a couple millimetres of freezing rain or freezing drizzle, and then a few millimetres of rain. This new storm layer may just look like a millefeuille or perhaps crème brûlée?!

The storm will pass right over the Chic-Chocs early Tuesday morning before pushing east. After a brief lull in the winds, they will whip around to west-northwest 50-70 km/h Tuesday morning causing freezing levels to plummet from 2500 metres back to sea level by noon. Temperatures will also fall steadily throughout the day from +1C in the morning to -8C by sundown. The crisp northwest flow will support light flurries all the way to Wednesday morning with 3-5 cm possible. High pressure will then build over southern Quebec on Wednesday providing increasing sunshine along with moderate NW winds. Temperatures will remain below seasonal with a high near -8C.

Cloud cover is forecast to increase Wednesday night followed by snow or a mix of rain and snow on Thursday as a second Colorado low approaches the region. The final storm trajectory remains to be confirmed, but there is currently moderate agreement amongst the models that the storm will track across the Saint-Lawrence Thursday night into Friday. Current estimates are for 5 cm of snow possibly mixing in with some rain, but we shall see. Another round of strong to moderate winds is also likely with this storm. Quieter, sunnier weather emerges next weekend.

Forecast Confidence :

Suffice to say that this is a tricky forecast and confidence is therefore moderate at best. While a considerable amount of warm air is certain to push in aloft, the amount of cold air that will remain locked in at the surface is questionable. If the depth of the cold air is shallower than forecast, we could end up with a higher ratio of freezing rain vs. ice pellets. However, as mentioned above, models have trended less and less with the freezing rain. The ensuing flurries Tuesday morning through Wednesday are also somewhat uncertain. Some models have but a trace of snow while others favor 3-5 cm. As snow lovers, we`ve favored the snowier solution 😊.