Tuesday, February 19, 2018  3:30 AM

There You Snow Again

Quiet Today Before Parade of Potential Snowstorms Second Half of Week

Our recent trend of missing potential snowstorms continued yesterday. A large area of clouds that was centered over the Dakotas ended up drying out leaving Minnesota with a good supply of sunshine (see Shortwave Albedo from Colorado State satellite slider). Given the sunshine and the light winds, high temperatures (see NWS high temperature map from University of Albany) that were still 10-15 degrees below average (highs are now supposed to be in the upper 20's) felt relatively pleasant. Overnight, the continued clear skies and calm winds have allowed temperatures to fall below zero in most of central Minnesota (see NWS Aviation Weather Center METAR map) with some temperatures in the minus teens near and past the Brainerd Lakes (see NWS: Last 72 hours of St. Cloud Observations). We will be able to eke out another snow-free day today, although the low clouds developing in Nebraska and Kansas (white areas on the Shortwave Albedo) could end up cutting down on our sunshine during the afternoon. Highs will stay in the teens.

However, the change in the main storm track I mentioned yesterday morning (and didn't push the post button until yesterday afternoon) is still in place with a strong southwest-to-northeast flow from the Southern Rockies to the Northeast (see Mid-Tropospheric water vapor loop from Colorado State satellite slider). This will allow a series of storm systems in the parade from the North Pacific, moving near or to the south of Alaska, then headed southeastward towards the US West Coast to move into the Southern Rockies and head for the Plains states. This Pacific water vapor loopfrom University of Wisconsin/SSEC shows a dark area that is a storm system pushing into the Aleutian Islands, another one just off the south coast of Alaska, another dark area moving through British Columbia and Alberta and the next storm system, the counterclockwise circulation center spinning over Nevada, Arizona, and Utah. The southern Rockies system is due to affect Minnesota from late tonight through tomorrow, the one in Alberta could drop some snow on Friday, and the one to the south of Alaska is forecast to become a major central US storm over the weekend. Because the developing high near the Bahamas has pushed the main storm track further to the north into the Northeast, it is going to be hard for any of these storms to miss all of Minnesota. While the details are still somewhat fuzzy, I find it believe there is a good chance of much of central and southern Minnesota getting at least 6 inches of snow from Wednesday through the weekend.

Wednesday Pre-Dawn to Early Afternoon Snow to Produce 4-7 Inches in Twin Cities, S MN; 2-4 inches in St. Cloud

The first storm system will push snow into the eastern Dakotas and southwestern Minnesota this evening with the snow beginning after midnight in St. Cloud and the Twin Cities. The period of snow will continue through the morning rush hour and into midday, before tapering to occasional snow showers and flurries. It looks like 4-7 inches of snow is likely from southwestern Minnesota across southeastern Minnesota and east central Minnesota, including Mankato and the Twin Cities. In central Minnesota to the north of the heaviest amounts, it appears that Willmar, Alexandria, St. Cloud, and Mora will pick up between 2 and 4 inches of snow. There will be new snow on the ground by the morning commute so traffic will have to slow down. The good news is that the actual storm won't be that strong, so there won't be huge problems with blowing and drifting snow. And, ground temperatures will be in the 20's, so salt and other chemical treatment will be able to work. The National Weather Service has a winter storm watch out from the eastern Twin Cities into southeastern and south central Minnesota. This will likely turn to an winter weather advisory for tomorrow.

We could see a prolonged period of flurries on Wednesday evening with some clearing by Thursday morning. Thursday should be our break with high temperatures in the 20s and light winds.

Another Light But Shovelable Snow Friday into Friday Night

However, what appears to be the weakest of the three storms in the forecast will again begin Friday to pump warm and increasingly moist air over the slightly colder than average air we have now. While this system appears to be the weakest of the three storms, it will have a bit more moisture to work with than tomorrow's system. So, we could end up with another light to shovelable snowfall. Snow will break out during Friday morning or midday and continue through Friday night. There is the potential of another 1-4 inches of snow from midday Friday through early Saturday morning.

Snow (or Mixed) Storm of the Century of the Weekend is Too Uncertain to Pin Down

Then, the potential strongest storm in the series will push into the Plains on Saturday and develop as it moves into the Mississippi Valley on Sunday. While I note above that it would be hard for this system to completely miss Minnesota given the main flow pattern, there are several questions. Will this really be the strongest storm in the series, or will it end up being no stronger than the systems earlier in the week? Will the track be far enough to the south to merely brush central Minnesota with snow while producing the heaviest snow near the Iowa border? Or will the storm track further north, raising the possibility of mixed precipitation or even rain in parts of southern and southeastern Minnesota while producing major snowfall amounts in central Minnesota. It's too early to answer any of that yet, because the run-to-run variation in the forecasts are pretty large. Still, there is certainly the potential of major snowfall (6 inches or more) in parts of southern and central Minnesota from Saturday night into Sunday night. My shoveling shoulder is aching already.

Confidence Level: "The Bulb on That Hard-To-Reach Light in the Foyer Will Burn Out"

Tuesday 2/19/2019: A sunny start, then increasing clouds and continued cold. High: between 10 and 15. Winds: SW 5-10 MPH. Chance of measurable snowfall: 10%.

Tuesday Night: Thickening clouds with light snow or flurries developing by late evening. Between 1 and 2 inches of new snow are likely by the morning commute. Low: between 7 and 12. Winds: SE 5-15 MPH. Chance of measurable snowfall: 20% evening, 70% after midnight.

Wednesday 2/20/2019: Light snow or flurries continues through the day, tapering to all flurries by middle afternoon. Another 1 to 2 inches are likely during the day on Wednesday. High: between 24 and 28. Winds: E 8-15 MPH. Chance of measurable snowfall: 60%.

Wednesday Night: Flurries ending in the evening, then partial clearing, and continued cold.. Low: between 9 and 15. Winds: NW 5-15 MPH. Chance of measurable snowfall: 20%.

Thursday 2/21/2019: Partly sunny, and seasonably cold. High: between 20 and 25. Winds: W 5-10 MPH. Chance of measurable snowfall: 10%.

Confidence Level: "Every Time I Try to Put in a New Bulb, the Light Fixture Will Try to Detach From the Ceiling"

Thursday Night: Partly clear early, increasing clouds late. Low: between 5 and 10. Winds: SW 5 MPH. Chance of measurable snowfall: 10%.

Friday 2/22/2019: Snow developing by late morning and continuing through the afternoon. High: between 22 and 30. Winds: SE 8-15 MPH. Chance of measurable snowfall: 70%.

Friday Night: Cloudy with snow continuing, tapering to flurries after midnight. Another 1-4 inches could accumulate Friday into Friday night. Not nearly as cold. Low: between 20 and 25. Winds: E-NE 5 MPH. Chance of measurable snowfall: 50%.

Confidence Level: "The Only Way I'll Be Able to Change the Bulb and Hold the Fixture in Place Will Be to Yell At It"

Saturday 2/23/2019: Cloudy with periods of freezing drizzle or flurries. High: between 28 and 32. Winds: NE 5-15 MPH. Chance of measurable snowfall: 40%.

Extended: More shovelable snow Saturday night and Sunday???

Forecast Confidence (10 - "The Rabbits Will Thump, Objecting to Me Yelling at the Light Bulb"; 0 - "I Will Be Hosting a DIY Show on Home Repairs"): 8 Tuesday, 7 Tuesday night, 6 Wednesday through Thursday, 5 Thursday night, 4 Friday and Friday night, 3 Saturday, 2 Sunday.

Yesterday's High: 18°F; Overnight Low (through 3 AM Tuesday): -7°F
St. Cloud Airport Total Storm Precipitation (through 3 AM Tuesday): None; SCSU Precipitation (through 3 AM Tuesday): None

Next Update: Wednesday, February 20, 2019 8 AM (or as needed)

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Let me know what you think about this forecast and discussion by emailing SCSU meteorology professor Bob Weisman. Please note that I make the forecast, not the weather!

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