Wednesday, September 10, 2014

It's Snowtember in the North

Snowy Calgary on September 8.
The forecast for much of the central and eastern U.S. has been calling for much cooler weather over the next few days. The cold air that will spread over the U.S. the rest of this week has already plunged into southern Canada and the northern U.S. Rockies. Calgary, Alberta has been hit hard by heavy, wet snow this week. On Monday Calgary picked up 11.8 cm (4.5 inches) of new snow, and on Tuesday an additional 1.3 cm (0.5 inch), and had 10 cm (4 inches) on the ground. This was all following a weekend with temperatures in the mid 70s Fahrenheit. The heavy, wet snow brought down trees that still were leafed out, and those in turn took down power lines. This morning an estimated 30,000 customers were without power. In addition to downed trees and power lines there were numerous traffic accidents, sort of typical for the first snow of the season, even in Canada. Some flights were delayed or cancelled at Calgary International Airport. Interestingly, schools remained open except for a few that had power outages.

This probably was a common sentiment
in Calgary. Photo by Deanna Allen
September snow is not that unusual for Calgary, with about 2 days of measurable snow on average. The snow Calgary has received this week is what they would normally receive for September and October combined. The snow continued today, and this morning Environment Canada issued a Snowfall Warning for the City of Calgary today with another 10 to 15 cm (4 to 6 inches) of snow expected. Except for damaged trees the snow will soon be a memory as a warmup is expected through the weekend and temperatures will be in the 70s Fahrenheit by early next week.

The cold air doesn't stop at the border, of course. Snow was falling in higher elevations in northern Montana today and Winter storm Warnings and Winter Weather Advisories are in effect until midday Thursday for areas on the east side of the Rockies as far south as northeastern Wyoming. Some snow also dusted the higher elevations in northern Colorado today.

View from Montana DOT camera at Two Medicine River  Bridge (elevation 4900 ft) near East Glacier at 6:19 p.m. MDT September 10
The higher mountains and passes could receive 6 to 12 inches of snow while the north-central plains pick up 1 to 3 inches. The southwestern valleys of Montana and lower elevations in Wyoming will see mostly a rain/snow mix.

Watches, warnings, and advisories in effect as of 6:27 p.m. MDT

As this cold air continues to spill south and east it will usher in an extended period of cooler than normal weather for the eastern two thirds of the country.

Minimum temperature forecast for Saturday, September 13

Maximum temperature forecast and departure from normal for Wednesday, September 17.

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