Black swan storm this week. A shot at 70 degrees late next week?
This week's heavy rain and snow event was a rare occurrence for Minnesota
Congratulations, Minnesota. You just lived through yet another truly rare extreme weather event.
Our massive three-day storm produced snowfall of 6 inches or more across more than 60 percent of Minnesota. That’s a big system.
But the truly rare event is that this storm dropped both a foot of snow and an inch of rain for areas around the Twin Cities. That hasn’t happened in at least 40 years, according to the Minnesota State Climatology Office.
Typically heavy Minnesota precipitation events like this occur and mostly rain or snow. Just how rare is it to get both a foot of snow and an inch of rain in the same storm?
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That’s hard to tease out of historical weather data. But it likely has only happened twice on record. Both the Halloween Blizzard of 1991 and the Armistice Day Blizzard of 1940 produced that kind of heavy rain and snow in the same storm.
Here’s more detail from the Minnesota State Climatology Office.
Over 60% of Minnesota received six inches of snow or more, with about a quarter of the state receiving at least a foot. Some of the highest totals were near Duluth and Brainerd, where observers with the National Weather Service and with the CoCoRaHS network reported over 20 inches of storm-total accumulation, including a report of 26.4 inches in the hills around Skyline Parkway on the west side of Duluth. The National Weather Service Cooperative observer northwest of Two Harbors reported 21.2 inches, with other observers in the area reporting over 18 inches of snow. The airport at Duluth received 17.7 inches, International Falls received 13.8 inches, and at the Twin Cities International Airport, the storm total was 12.1 inches, with a daily record 8.2 inches falling on the 24th. The snow from this system equaled -- or in cases like Brainerd -- exceeded snowfall totals from the entire snow season up to that point, which illustrates the unusual size of this storm given the season during which it occurred.
Precipitation
Heavy snow is always the big attention-getter during winter, but this system was equally significant for its total precipitation. The southeastern half of Minnesota received at least 1.5 inches of total precipitation, and the southeastern quarter of the state received over two inches, with some areas approaching three. This event, therefore, erased the precipitation deficits that had developed since early winter in some areas.
Rare Combination of Heavy Snow AND Heavy Rain
Areas in and near the Twin Cities, including the MSP airport, did something unusual: they received both a foot of snow or more and at least one inch of rain, from the same storm. It is difficult to track down historical occurrences of this type of pairing, but we know it is rare. It certainly has not occurred in the Twin Cities during the past 40+ years. During the infamous Halloween Blizzard of 1991, some communities in far southern Minnesota received well over an inch of rain, and then a foot of snow. Something similar occurred over a larger area during the great Armistice Day Blizzard on 1940. These were both historic, generational events. The storm of March 2024 is not on their level, but its meteorological feats were rare indeed!
March 28, 2024
Wintry mix up north
A winter weather advisory is up for most of northeastern Minnesota and northwestern Wisconsin into Saturday morning.
Expect some light ice and snow overnight into Saturday morning.
North St. Louis-Northern Cook and Lake-Central St. Louis- Including the cities of Ely, Isabella, and Hibbing
152 PM CDT Fri Mar 29 2024
...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO 10 AM CDT SATURDAY...
* WHAT...Mixed precipitation expected. Total snow accumulations of 1 to 3 inches and ice accumulations of a light glaze.
* WHERE...North St. Louis, Northern Cook and Lake and Central St. Louis Counties. This includes the Tribal Lands of the Bois Forte Band, Nett Lake and, Lake Vermilion areas.
* WHEN...From 9 PM this evening to 10 AM CDT Saturday.
* IMPACTS...Plan on slippery road conditions.
Highs this weekend will run in the 30s north to 40s south.
Warmer late next week
Much warmer air will blow into Minnesota late next week. Temperatures in the 60s look likely by next Friday. And some models are cranking out the year’s first 70-degree temperatures next weekend.
Stay tuned.