Discussion: Extremes breed more extremes…that’s certainly the weather story for the upcoming week. The record warmth affecting much of the eastern half of the county into early October fades. And now…just the opposite issue appears. Historic early season snows and attendant cold for the northern Rockies extending to the North-central States this week.
Snow cover is gathering early this week across Canada where west and central Canada snow cover is already ahead of schedule. Presence of the snow cover enables locally cold air masses to evolve and drop into the U.S. This week brings one of those events but with unusual caveats.
The clash of the evolving chill the moist warm air to the east sets-up a vigorous slow-moving frontal system and through dynamic forcing caused by the extreme climate conditions either side of the front creates a snow storm likely to be classified a blizzard for mid-to-late week over the northern Great Plains.
The latest GFS forecasts 2-3 feet of snow on the northeast North Dakota/Canadian border with several in. of snow as far south as Nebraska. Heavy snows will extend into Minnesota later this week.
Of course frigid air (and wind) accompanies the snowstorm with 20’s at night and low 30’s daytime during the storm and teens at night once the storm has ended. Unclear is how far to the east does the cold air mass penetrate. <32F risk is implied for the western Corn Belt and south to Oklahoma. But a hard freeze (<28F) is less certain.
Medium-range forecasts are warmer but snow cover may be so deep that any warming is resisted after 10 days for the northern Plains.