October blizzard likely in North Dakota; first Twin Cities' flakes of season?

Heaviest snow and wind likely targets eastern North Dakota

A winter storm watch is already up for a big chunk of territory bracketing the Red River Valley. And blizzard watches and warnings may be issued soon.

Grand Forks NWS office
Grand Forks, N.D., National Weather Service office
National Oceanic and Atmospheric Administration | National Weather Service Grand Forks

Our major early-season winter storm now looks highly likely for eastern North Dakota and the Red River Valley. Much of northwest Minnesota will see wintry conditions by Saturday. And all of us will feel the season’s biggest major temperature crash so far.

Let’s dig into the meteorology of the first major wintry storm of the season.

The system

Our inbound low-pressure system swirled out of the Gulf of Alaska over the weekend. It pushed onto the west coast near Seattle Tuesday. The storm drops to the Four-Corners region Thursday then races northeast toward the Upper Midwest Friday.

Likely storm track
Likely storm track
NOAA/National Weather Service Grand Forks

The system is already producing snow in the Cascades.

The surface low-pressure system winds up west of Kansas City Thursday morning, then races north toward the Twin Cities into northern Minnesota Friday. As the system moves north, cold air behind the storm feeds in, deepening the storm.

The Canadian model seems to have a decent handle on the storm track and rain-snow coverage as the system moves north.

Canadian model Thursday through Saturday morning
Canadian model Thursday through Saturday morning
NOAA via tropical tidbits

It appears the Twin Cities will stay on the rainy side of the storm until late Friday night or Saturday morning.

Snow zone

There is more model consensus today that the most likely heavy snow zone will layout across eastern North Dakota. The suite of forecast models now mostly agree on a band of 1 to 2 feet of snow, with some high-end totals to over 30 inches possible. Snowfall totals taper off as you move east into northwest Minnesota, where much of the precipitation should all as rain in the early part of the storm.

Here’s the Tuesday morning Canadian model snowfall output by Sunday morning. Keep in mind this map will almost certainly not verify precisely, but it’s starting to look like the most likely general pattern.

Canadian model snowfall output by Sunday morning
Canadian model snowfall output by Sunday morning
Environment Canada via pivotal weather

In this scenario, the Twin Cities could get sideswiped by some snowflakes and minor slushy accumulation Friday night into Saturday morning.

Blizzard potential

As cold air rushes in to deepen the low, high winds on the storm’s backside will drive sustained winds that could reach 40 mph Friday night. Gust may top 50 mph in eastern North Dakota. NOAA’s GFS model cranks out sustained winds of 34 knots (39 mph) Friday evening across eastern North Dakota.

NOAA GFS 10-meter winds Friday evening
NOAA GFS 10-meter winds Friday evening
NOAA via tropical tidbits

Blizzard conditions would occur under this scenario. Watch for blizzard watches and warnings to be issued in the next 24 hours.

Deja Vu

This storm arrives almost precisely a year after last October’s storm in eastern North Dakota.

Stay tuned for possible forecast model changes as the system unfolds.

Temps crash

This system rams the season’s coldest air so far into Minnesota.

Temperature forecast for Twin Cities
Temperature forecast for Twin Cities
NOAA via Weather Bell

Ther are signs temperatures may return to the 60s around the weekend of Oct. 19-20 in the Twin Cities and southern Minnesota.