Thursday, September 26th 2019, 8:26 pm - High impact snow storm has already prompted winter storm watches for parts of the western Prairies. The time to plan ahead is now.
September snowfall records are in jeopardy and this significant storm is threatening to dump 60+ centimetres of snow on parts of the Prairies. This storm will begin on Friday and will linger into Monday morning.
"It's time to change your travel plans across Alberta and Saskatchewan," warns Weather Network meteorologist Tyler Hamilton.
We take a look at the abrupt change to the pleasant fall conditions, and why there are concerns for travel, agriculture and power outages throughout this weekend, below.
Visit our Complete Guide to Fall 2019 for an in-depth look at the Fall Forecast, tips to plan for it and a sneak peek at the winter ahead
- Sharp drop in temperatures into the weekend
- Snow begins late Friday, lasting through to Monday morning
- Strong winds make for blizzard conditions in extreme southern parts of Alberta and Saskatchewan
- Stay on top of ALERTS in your area
WATCH BELOW: TIMING THE WEEKEND WINTER STORM
This brewing storm has the potential to be talked about for years to come as conditions align for what could end up being an historic early fall snow for parts of the Prairies. Even the U.S. National Weather Service, which is watching its effects south of the international border, said it has the potential to become the "new benchmark" in winter storm watches issued for parts of Montana.
WEATHER WARNINGS AND ALERTS: Stay prepared, here
An upper-level low pressure system over the northern Prairies has been strengthening as it moved toward Hudson Bay for the past few days. Now that it's arrived over northern Manitoba, a block in the jet stream has left it with nowhere to go. That brief block will leave the upper low spinning in place into the weekend, pumping cold air down from the Arctic into next week as well.
That means most places are in for a 20-degree temperature drop from the start of the work week to the end, making the region primed for some significant autumn snow.
WINTER STORM WATCHES IN EFFECT
Environment Canada has issued winter storm watches for parts of extreme southwestern Alberta and special weather statements are in place for majority of this province. These alerts have been issued ahead of what is expected to be a long-duration snowfall event lasting from late Friday to Monday morning, with hefty amounts along an area stretching from Alberta’s southwest through to southern Saskatchewan.
"This may be the most snow you see through the fall, and even the winter months through this season ahead," says Hamilton.
Hamilton says there are parts of the high mountains of the southwest that could see 60 hours or more of snowfall, possibly racking up as much as a metre of snow over the duration. Most places won't come near that level, but amounts of 30-60+ cm aren't out of the question for the worst-hit areas.
The greatest snowfall amounts are likeliest in the southwest and along extreme southern parts of Alberta and Saskatchewan, with major cities like Calgary likely picking up between 5-10 cm, although with potential for more significant accumulations.
UPSLOPE FLOW WILL ENHANCE SNOWFALL AMOUNTS ALONG HIGHER TERRAIN
Snow is not out of the ordinary at this time of the year on the Prairies, but a peculiar setup is behind these expected extreme amounts.
By later Friday afternoon, the first flakes are likely to fall at the higher elevations of the mountains and foothills, courtesy of an upsloping effect -- air being forced up the mountainside to higher, colder altitudes, shedding its moisture as precipitation.
The real snowmaker will be a developing Colorado low -- so-named for its origins near the U.S. state of the same name -- as it spills its moisture north of the border on Saturday and collides with the colder temperatures of the region.
Hamilton says travel will not be recommended not only in the mountains, but also the most southerly parts of the Prairies. Strong winds Saturday and Sunday, possibly gusting upwards of 50 km/h, will make for some dangerous blizzard conditions.