Weekend forecast: warmest temps on Saturday, with shower chances to the north

Snow last Sunday changed us from mild to moderate on the snow and cold index

It’s nice to see temperatures edging upward today, and that trend continues on Saturday.

Our average Twin Cities high temperature on April 18 is 59 degrees. We’ll probably top 60 degrees Saturday afternoon in much of the Twin Cities metro area. Southern Minnesota will see a lot of highs in the 60s on Saturday:

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Saturday forecast highs
National Weather Service

There’ll be many highs in the 50s elsewhere, with some 40s in far northern Minnesota.

Winds will pick up a bit on Saturday, with afternoon gusts over 20 mph in many areas:

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Saturday 1 p.m. forecast wind gusts
National Weather Service

Plotted values are in knots, with 18 knots equal to around 21 mph.

Sunday highs will retreat to the lower 50s in the south, with 40s in northern and central Minnesota:

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Sunday forecast highs
National Weather Service

Shower chances

Rain showers are expected to move into parts of northwest Minnesota late Friday night, then spread eastward. Roughly the northern third of Minnesota will have a chance of scattered showers on Saturday. A few snowflakes may mix with the rain showers early Saturday.

The National Oceanic and Atmospheric Administration’s North American Mesoscale (NAM) forecast model shows the potential precipitation pattern Friday night through Saturday evening:

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Simulated radar Saturday night through Sunday evening
NOAA, via Tropicaltidbits.com

The NAM model shows a shower chance in the metro area and southeastern Minnesota late Saturday evening, but that shower chance is missing in some other forecast models.

You can hear updated weather information on the MPR network, and you’ll see updated weather info on the MPR News live weather blog.

Snow and cold index shifts

The Minnesota State Climatology Office has a Snow and Cold Index that allows us to compare the severity of our “winter” weather year to year. We all know that “winter” in Minnesota starts in late fall and often continues into early spring.

Here’s how the Snow and Cold Index (SCI) works:

The Twin Cities Snow and Cold Index (SCI) is an attempt to weigh the relative severity of winter when compared with winters of the past. The SCI assigns single points for daily counts of maximum temperatures 10 degrees F or colder, and daily minimums of 0 degrees F or colder. If the minimum temperature drops to -20 degrees or colder greater, eight points are attributed to that day. Snowfall totals of one inch or greater in a day receive one point. Four-inch snowfalls generate four points for the day, an eight-inch snowfall receives a whopping 16 points. To quantify the duration of winter, one point is tallied for every day with a snow depth of 12 inches or greater.

The snow and cold index for our 2019-2020 “winter” in the Twin Cities was sitting comfortably in the mild category until last Sunday. Last Sunday’s 6.6 inches of snow at MSP airport gave us 5 points; 1 point when the snow total reached one inch, and an additional 4 points for reaching 4 inches.

Our 2019-2020 snow and cold index is now at 55 points for the Twin Cities:

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Twin Cities snow and cold index
Minnesota State Climatology Office/Minnesota DNR

That’s at the very bottom edge of the moderate range, which runs from 55 to 148 points. By comparison, we tallied 207 points during the severe winter of 2013-2014 in the Twin Cities.

Last winter was much colder and snowier than this winter in the Twin Cities; here are the details from the Climatology Office:

So far the 2019-20 winter has 55 points: 22 points for cold, 33 points for snow, just enough to be in the "moderate" winter range.

The 2018-19 winter had 157 points: 63 points for cold, 94 points for snow. This was enough for 2018-19 to be categorized as a "severe" winter.

On a positive note, we won’t be adding to our SCI in the next 7 days. We’re ready for spring!

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