Winter season severity index off to a slow start in Minnesota

I’ve written more than once this fall about our likely Super El Niño-driven winter. Thanks to a massive patch of super warm water in the tropical Pacific Ocean, the odds strongly favor a milder-than-normal winter in Minnesota.

Yes, we’ll still get snow and some bitter air masses from time to time. But in the end, this winter is likely to feel a bit less harsh.

So far, so good for El Niño in these last days of November. Even with our recent cold snap, we’re still running more than 2 degrees warmer than normal in the Twin Cities and most of Minnesota this month. This is the seventh straight warmer-than-normal month in Minnesota.

See the chart at the top of this post? It shows the Accumulated Winter Season Severity Index for the Twin Cities so far. We’re running in the moderate range so far.

Check out Duluth’s chart below. The Twin Ports area is having an almost balmy November compared to normal.

Here’s more on how to use the AWSSI from the Midwest Regional Climate Center:

Goals of the AWSSI

Use max/min temperature, snowfall, and snow depth to objectively index winter weather conditions.

Create a historical database of AWSSI for locations with available temperature, snowfall and snow depth.

Compare season to season AWSSI for a particular location in climatological context.

Allow users access to objective data to make winter-informed decisions, especially pertaining to snow removal, commerce, and transportation.

Defining the AWSSI Season

The AWSSI is not limited to meteorological winter (December ‐ February) but is intended to capture winter weather from its earliest occurrence to its last.

The winter season begins with the first occurrence of any one of the following:

• First measurable snowfall greater than or equal to 0.1 inch.

• Maximum temperature less than or equal to 32°F.

• Winter season begins on December 1 if conditions above have not been observed.

The winter season ends with the last occurrence of any one of the following:

• Last measurable snowfall greater than or equal to 0.1 inch.

• Last day with 1 inch of snow on the ground.

• Last day with max temperature less than or equal to 32°F.

Winter season ends February 28/29 if the above conditions have occurred.

It’s going to be interesting to see how December temperatures wrap up the year. Right now, forecast models for next week favor a return to warmer-than-normal temperatures.

And the National Oceanic and Atmospheric Administration’s three to four-week outlook paints a red bull's-eye of likely warmth right over Minnesota.

So the odds favor a warmer-than-normal December. If it happens that will be eight straight warmer-than-normal months to close out 2023.

We average about 51 inches of snow in the Twin Cities each year. I have a hunch we may end up closer to 40 inches, or less this winter.

Stay tuned.