Frigid temperatures this weekend prompt cold weather advisories

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. Do AWIPS, ASOS, COMET, NOAA, OBVIS, and SPC float your weather boat? 

, which is calculated and published by the Midwest Regional Climate Center.

The AWSSI quantifies the severity of the winter season by assigning points to various winter weather parameters. 

Subzero temperatures? Add seven or more points. Minus 20 this morning? Another 15 points. A fresh foot of snow? Another eight points for what fell; tack on another 20 or more each day for having that much snow depth on the ground.

Here’s more detail on how the AWSSI accumulates points during the winter season.

Daily scores are calculated based on scores assigned to temperature, snowfall, and snow depth thresholds. The daily scores are accumulated through the winter season, allowing a running total of winter severity in the midst of a season as well as a final, cumulative value characterizing the full season. Accumulations of the temperature and snow components of the index are computed separately and then added together for the total index. This allows comparison of the relative contribution of each to the total score.

The Twin Cities AWSSI number of 438 through Jan. 6 shows an average winter so far. 

Winter has been more severe in Duluth (722) and the Red River Valley. (758)

If one winter index is good, two is better right? Like many things, winter severity depends on how you measure. 

 for the Twin Cities calculates a much milder winter so far. The accumulated value of just 22 points puts this winter solidly in the very mild category so far.

Why the difference? The points systems for snow, snow depth, and cold on the two indexes differ. 

So depending on how you measure, it’s been a mild to moderate winter in Minnesota so far.

Weather and Climate News

Updraft® - Minnesota Weather News

Paul Huttner

Author

The numbers show the has been an average winter for the Twin Cities area. It’s been more severe in Duluth and the Red River Valley.

The Nicollet Mall at snow- and ice-covered Eighth Street.

Tim Nelson | MPR News file

Accumulated Winter Season Severity Index (AWSSI) points threshold 

Midwest Regional Climate Center

Duluth Accumulated Winter Season Severity Index (AWSSI) 

Accumulated Winter Season Severity Index (AWSSI) 

Has it been an average or mild Minnesota winter so far?

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