Thursday rain to snow; some accumulation Thursday night

Astronomical spring begins at 10:50 pm Thursday with the Vernal Equinox. But the weather maps insist on one more shot of wintry weather.

March in Minnesota brings radical weather extremes. The Twin Cities bottomed out at minus 23 on March 1, 1962. And the mercury has soared to 83 degrees on 3 different days in late March. That’s a 105-degree historical temperature range in March for the Twin Cities.

So it’s not a big shock to see a potent storm system with rain and snow on the spring equinox.

Forecast models are still all over the map with a snowfall forecast for Thursday evening. Let’s break down what we know, and what’s still uncertain with Thursday, inbound storm.

The system

Thursday’s inbound storm winds up in eastern Colorado, then races northeast from Kansas to the Great Lakes by Friday morning. It’s a fast-moving, quick-hitting system. Expect mostly rain Thursday, then a rapid transition to snow by Thursday evening.

Here’s NOAA’s GFS model sequence of events.

Look for the transition to snow to hit the Twin Cities area late Thursday afternoon into Thursday evening. I expect a few hours of big wet flakes Thursday evening. The snow will taper off from west to east overnight.

Soaking rains

Most of the precipitation with this system will actually fall as rain Thursday. Rainfall totals over an inch are likely in much of southern Minnesota.

We could see a few embedded thunderstorms from the Twin Cities south to the Iowa border. There will likely be a severe weather outbreak across Iowa and Illinois. Check out the enhanced severe risk areas. It won’t be long now until we see those creep north into Minnesota, weather fans.

Snowfall totals: Big model spread

There is still a significant model spread in forecast snowfall locations and totals. Some models project little snow for big chunks of Minnesota and some have several inches in the same spot.

NOAA’s GFS model suggests a wide area of accumulating snow.

The European model suggests a pocket of a few inches from the southern Twin Cities southward.

And the Canadian and UKMET models suggest most of the snow will stay south fo the Twin Cities, with another band of snow across northern Minnesota.

With so much model spread there is still high uncertainty in snowfall totals. So expect rain to change to snow late Thursday and a decent shot of snow for a few hours Thursday night.

My best read is to expect a broad area of 1 to 3 inches generally south of a Granite Falls to St. Cloud to Duluth/North Shore line. There could be some local 4 to 5-inch totals in that zone.

Stay tuned as we tweak the forecast later tonight and Thursday.