It was a topsy-turvy Tuesday when it came to the weather in Calgary. The day started out warm and stable, with sunshine and calm winds, allowing the city to warm up to a high of 10 C by 2 p.m. Then, an incoming mass of arctic air from the north drove temperatures down to -6 C by 5 p.m. The cooldown was fuelled by gusty northerly winds between 30 to 50 kilometres an hour that set the stage for a pre-frontal inversion. This type of inversion ushered low-lying dust and other particulates that accumulated during the warming period above the surface into Calgary ahead of the cold front, causing an air quality health index (AQHI) reading of four, or moderate risk. As the cold air continued to push into Calgary, it clashed with the earlier warm air to produce light snowfall between 5 and 6 p.m. Models seem to be caught off guard by the precipitation potential from the cold front, so there’s not a lot of agreement as to how long the flurries will fall, and on and off flurries are likely to continue throughout Wednesday with a seasonal high of 2 C. By Thursday, the jet stream starts to re-position to allow a ridge of high pressure to briefly settle over the Rockies. This could bring chinook winds and double-digit temperatures back to Calgary by the weekend.
