Blizzard warnings: Complex wind, snow and sleet storm peaks Thursday

A powerful out-of-season winter in spring storm is still on track for Minnesota.

This system is complex. It has several competing meteorological factors working in some areas while at the same time focusing all the elements for heavy snow and blizzard conditions in western Minnesota. Forecasting this one correctly for all points in Minnesota is starting to look like a meteorological high-wire act.

Buckle up.

High confidence areas: blizzard warning

One way to think about this evolving storm is to define areas of higher vs. lower forecast confidence. One area with higher forecast confidence is western Minnesota. Almost every forecast model favors western into central Minnesota as a high probability zone for the heaviest snowfall and highest winds. That’s the zone that is likely to pile up 10 to 20 inches of snowfall totals by Friday and to experience ferocious blizzard conditions Thursday.

That higher confidence level is reflected in the latest National Weather Service Twin Cities’ situation report, and why a blizzard warning has been issued there.

Including the cities of Morris, Glenwood, St Cloud, Madison,
Benson, Montevideo, Willmar, Litchfield, Granite Falls, Olivia,
and Redwood Falls
404 PM CDT Tue Apr 9 2019

…BLIZZARD WARNING REMAINS IN EFFECT FROM 7 PM WEDNESDAY TO 7 AM
CDT FRIDAY…

* WHAT…Blizzard conditions expected. Total snow accumulations of
12 to 18 inches with isolated 20 inch amounts possible. Winds
gusting as high as 45 mph.

* WHERE…Portions of central, southwest and west central
Minnesota.

* WHEN…From 7 PM Wednesday to 7 AM CDT Friday.

* ADDITIONAL DETAILS…Travel could be very difficult to
impossible. Areas of blowing snow could significantly reduce
visibility. The hazardous conditions could impact the morning
or evening commute.

The Twin Cities and much of Minnesota remain under a winter storm watch.

Twin Cities weather slushy? Models edging north

Some but not all of the forecast models today favor a slightly more northerly track. That brings a warmer layer of air perilously close to the Twin Cities for forecasters. The rain-sleet-snow transition zone looks like it may make it close, or into the Twin Cities Thursday.

That could mean a few hours of rain and or sleet pinging off windows, maybe even accumulating “shovelable” sleet. That mix will cut down snowfall totals where it happens. But it will still be a mess.

The National Oceanic and Atmospheric Administration’s North American Mesoscale Forecast System 3 km model captures the trend of the rain-sleet-snow transition zone working to near the Twin Cities by Thursday. If this pans out, it will be a full-blown sleet storm with a snowy topping for the Twin Cities. A weather-slushy anyone?

National Oceanic and Atmospheric Administration’s North American Mesoscale 3 km model Wednesday and Thursday via tropical tidbits.

Snowfall totals

At this point, I still like the looks of NOAA’s Global Forecast System model’s overall snowfall solution. It brings the heaviest snow to western and central Minnesota. The Twin Cities rides the edge of the transition zone.

My read as of now is that we’ll see a big range of snowfall across the Twin Cities from southeast — less snow, more sleet — to the northwest — more snow. I think the most reasonable forecast is a range of about 5 inches in the far southeast Twin Cities like Hastings and Lakeville, to as much as 15 inches in the far northwest metro edge communities like Rogers, Elk River and Maple Grove.

NOAA GFS snowfall output via pivotal weather.

The Twin Cities NWS version of events reflects the lower forecast confidence for the Twin Cities area.

Tornado drill canceled

Here’s another one I’ve never seen before. The Twin Cities NWS has canceled Thursday’s scheduled tornado drill because of the inbound winter storm system. Only in Minnesota.

Stay tuned to see what model changes we see Wednesday before the bulk of the storm arrives Thursday.