We have been enjoying unusually mild weather this week, with day time highs of 15° C or higher. But the threat that the coming weekend will bring an abrupt switch to winter has been hanging over our heads since last Sunday. A Colorado low has been tracked all week and is forecast to reach us tomorrow, Saturday, with the full storm arriving Sunday.
A Colorado low is a low pressure system beginning in that southwestern state and tracking northeast towards Canada, picking up moisture along the way and dumping it upon us. The forecast is for 30 to 40 cm of snow and winds gusting up to 70 k/hour. Monday morning could look like this.
Most of us have heeded the warnings and put our lawn chairs and lawn mowers away for the winter. I expect retail outlets have seen a rush on sales of snow shovels and winter apparel. Children are looking forward to playing in the snow, some adults are looking forward to a few days of remunerative work in removing the snow from streets and parking lots.
The main advantage for the rest of us is that it gives us something new to talk about, and blog about.
Flatlander Faith 
Now you have me trying to remember what the Calgary something or other was back when I was living in Washington state. It was a brutal weather system, indeed.
Among the weather systems that have names is the Chinook. It happens when warm air comes over the Rockies and sinks to ground level, pushing clouds and cold air higher. A warm wind comes across southern Alberta and into southwestern Saskatchewan, often producing a dramatic snow melt in a few hours. We are beyond the reach of the Chinooks here. Another named storm system is the Alberta Clipper. It usually starts a little further north at the foot of the Rockies and quickly tracks southeast through Saskatchewan and into southern Manitoba. It produces blizzard like conditions along its path, but doesn’t leave much snow. Albertans don’t like us to call it the Alberta Clipper, but that’s where it starts.