Published on
December 18, 2024Effective for
December 18, 2024 to December 21, 2024Short and medium-term outlook
Trending snowier
A frontal system (warm front followed by cold front) crossed the Chic-Chocs on Tuesday generating precipitation and strong southerly winds. While it rained along the coast and in the valleys, alpine temperatures only rose to +1C for a few hours so the precip fell as a mix of snow and rain up high. In the wake of the system, a cooler westerly flow will maintain mainly cloudy skies and light (20-40 km/h) winds on Wednesday. Temperatures will steadily fall through the day to reach -3C in the afternoon.
Light snow will develop around midnight Wednesday as a trough sweeps in from the west and will continue most of the day Thursday. Models are in fairly good agreement with 5-8 cm expected in the mountains. Worth highlighting are the higher amounts along the coast and in the foothills where upwards of 15-20cm will be possible. Alpine temperatures will be near -5C making for relatively light, fluffy snow. Winds will start off light from the southwest Thursday morning then shift to gusty northwesterlies in the wake of the trough in the afternoon. Winds will ease Friday with partial clearing as a temporary ridge of high pressure builds in.
The weather pattern gets interesting heading into the weekend. Models are in good agreement with a Nor’easter type storm moving up the American seaboard on Saturday to reach western Newfoundland by the afternoon. This trajectory will position the Chic-Chocs in a cold northerly flow and on the periphery of the precipitation. Models currently suggest 5-10 cm on Saturday with moderate (40-60 km/h) winds. It is worth emphasizing how changeable the trajectory of these Nor’easters can be. A minor deviation towards the west could significantly increase snowfall amounts while an easterly push would leave us high and dry. Needless to say, there remains uncertainty with Saturday’s snowfall so stay tuned to Environment Canada forecasts heading into the weekend. Looking further into next week, the period leading into Christmas looks cool with light flurries.
Forecast Confidence :
Good confidence with the quiet pattern Wednesday. Snowfall amounts on Thursday are somewhat uncertain, particularly between the foothills and the coast where some models suggest bullseyes as high as 30cm. As mentioned above, confidence falls to poor this weekend given the fickle nature of Nor’easters. Time will tell!