Weather whiplash in southern Quebec

The first snow of the season in Vaudreuil last weekend, did not last long, as warm air returned by mid-week. (ValleyWX)

After a record breaking warm October in Ontario and Quebec, November is proving to be anything but certain. If you are not sure which jacket to grab in the morning, you are not alone. The change in temperature from day to day is enough to give you whiplash. With a predominate west to east "zonal" flow in place across Canada, weather systems have been moving rather quickly, producing highly variable weather. On Sunday, November 19, Montreal recorded the first measurable snowfall of the season, with anywhere from 2-5cm falling. Monday was windy and bitter cold, with snow flurries and temperatures at -6C (21F), windchill values were as cold as -18C (0F) However, just 24 hours later the temperature was 8C (48F), with bright sunshine. This pretty much describes the month we have had in Montreal, from mid-winter cold, to near record-breaking warmth and back again, at times in just a few hours.

That brings us to this weekend, where pretty much the same pattern is in place. The current weather is being produced by a potent cold front slipping across the St. Lawrence Valley. A steady rain in Montreal, will slowly taper to a few flurries tonight. Gusty west winds will increase up to 50km/h this evening. Temperatures in southern Quebec today are in the 5 to 10C (40 to 50F) range. Behind the front, cold air will surge into the region, with lows down to -4C (26F) by Sunday morning. Sunday will be windy and cold, with flurries and temperatures remaining steady. Yet another clipper system will arrive late Sunday into Monday, with some light snow and chilly temperatures. However, the cold will not last long. By Tuesday, more mild air will surge into the region, with temperatures well above normal expected for most of the upcoming week. As long as this flat, zonal pattern remains in place, the arctic air will remain trapped across the far north, with any storm systems being rather weak and moisture starved. I expect a change by the second week of December.