Western snow - Eastern rain

By the way, it is now officially the Holiday Season. The Tim Hortons Christmas cups are out! I received my first this morning.

The tranquil weather of the last few days is about to come to an end here in the east. Low pressure over the lower Mississippi Valley will lift northeast towards the St. Lawrence Valley. It will bring with it a swath of steady rain that is increasing in coverage and intensity this morning. Environment Canada has posted heavy rainfall warnings for the regions just north of Montreal and the Ottawa Valley. Rain will begin this evening and become heavy overnight. Rainfall accumulations of 30-50mm are expected in the warning area with 25-35mm elsewhere including Montreal. The system is strengthening and so are the winds associated with it. Look for winds to increase from the south and southeast between 30-60km/h with stronger gusts over the higher elevations. Winds will back around to the northwest Wednesday but remain strong. Temperatures will be mild at first but begin to lower on Wednesday. There is even the risk of an isolated thunderstorm across the area tonight.

Meanwhile the opposite is occurring in the west with winter storm warnings in effect for southwest Saskatchewan and southern Alberta. This morning snow is falling in Calgary with north winds gusting to 54km/h and a temperature of -7C. Winds are howling in southern Alberta over 70km/h with low visibility in blowing snow. The snow and strong winds will move into Saskatchewan early this morning with 15cm or more of snow expected in the Cypress Hill and from Swift Current west to the Alberta border. In addition to the snow, bitter cold is descending south and east behind the storm. Look for the coldest air of the season to spread across the west and eventually into Ontario. Low temperatures will be in the minus teens for the rest of the week with daytime highs no better than -5C. The air will modify slightly before reaching Quebec but it will still be cold enough for some snow by Sunday.