Season's biggest snowfall likely starting Sunday

How high will it go? That’s the biggest forecast question at this point on Friday afternoon looking ahead to Sunday and Monday.

Our inbound storm system has a lot going for it to produce some impressive heavy wet snowfall totals across much of Minnesota.

We enjoy a quiet Saturday before the snow flies for real on Sunday.

I keep looking for reasons to forecast less snow than what the most conservative models are cranking out, but so far I don't see it.

If warmer air pushes farther north than expected Sunday night, that could cut snowfall totals accordingly from the Twin Cities southward. Compaction of the heavy wet snow and some melting will reduce how much snow is on the ground versus what actually falls and is measured between clearing snow measurement boards.

The great news? It looks likely this system will drop 1 to 3 inches of liquid equivalent precipitation over the next few days.

Let’s break down what looks likely to be the biggest snow producer of the season.

The system

A powerful low-pressure system is plowing into the Oregon coast as I write this Friday afternoon.

The system will cross the Rockies and gather in Colorado Sunday before tracking northeast toward Minnesota Monday.

One impressive feature of this system is the wide open tap to Gulf of Mexico moisture. Watch the system tap into a juicy moisture tongue represented by higher dew point values surging north between Sunday and Monday.

Most forecast models agree on some possible light snow overnight Saturday night. But the main wave of heavy wet-cement snow pushes into southwestern Minnesota early Sunday morning.

The heavy snow bands look likely to reach the Twin Cities and much of central Minnesota by midday Sunday.

The heaviest snow bands are likely Sunday afternoon through Sunday night. Then most models suggest a change to rain from the Twin Cities southward on Monday.

Here’s the National Oceanic and Atmospheric Administration’s Global Forecast System model sequence of events between Sunday and Tuesday:

Best estimate for snowfall totals

You have probably noticed I haven’t posted forecast models for snowfall output this week. It seems sensible to get through one storm at a time. The forecast models did a good job overall with our Thursday night snow.

Now we focus on Sunday’s event. There’s still time for forecast models to change dramatically before the snow flies Sunday.

Right now I am leaning toward a Monday change to rain from the Twin Cities south. The sooner that happens, the less snow we’ll see. If it happens later or not at all, the Twin Cities would get in on the heavier snowfall totals.

My best estimate now is for a range of between 6 and 12 inches of sloppy wet snow by Monday morning across the Twin Cities. The heaviest totals favor the northwest Twin Cities.

I would say the European Centre for Medium-Range Weather Forecasts model snowfall output as of Friday afternoon seems reasonable for southern Minnesota and the Twin Cities:

The best chance for snowfall totals between 1 and 2 feet runs from southwestern Minnesota through Willmar and St, Cloud, and possibly to Brainerd and the North Shore.

I like the notion of the Friday afternoon Duluth National Weather Service office update on snowfall totals:

Here’s the Twin Cities National Weather Service office snowfall projection:

This system is coming with plenty of wind too. So expect a wind-driven heavy wet snow event. Travel will likely be very difficult much of Sunday through Monday across western and central Minnesota to the North Shore.

Forecast models suggest temperatures from the Twin Cities south on Monday could reach 40 degrees. So roads may improve as we move through Monday in the Twin Cities.

You had to know our warmest winter on record move would end with a snow blitz.

Stay tuned to Updraft over the weekend as we update forecast model trends and snowfall timing and coverage.