Our snow event for tonight is coming together with a surge of warm/moist advection lifting north on southerly winds ahead of a low pressure system and trough which is approaching from the northern Plains. Arctic airmass which has been over the area the last few days has now pushed into eastern Canada and northeast U.S. today.
…Here’s my updated snowfall forecast for tonight’s event…
•This will be a fluffy snow with snow ratios expected to be in the 15:1 to around 20:1 range.
•Should see larger snowflakes at times with a favorable dendritic growth zone (DGZ) in place especially late tonight-early Tue AM. This is when we should see the bulk of the accumulating snow occur across the area.
•1 to 3″ for most of northwest Wisconsin and up in the extreme NW portion of northern Minnesota
•3 to 5″ for the Twin Ports, North Shore areas, west toward Aitkin and Brainerd, and also in far northwest Wisconsin.
•A swath of 5 to 7″ roughly along and north of Highway 2 in northeast Minnesota.
•The Tuesday morning commute could be impacted by snow with slippery travel conditions possible.
Link to road conditions
Wisconsin — https://511wi.gov/map#:Alerts
A band of snow stretching NW-SE from northwest Minnesota to northwest Wisconsin continues to lift slowly to the E-NE early this evening (Radar loop ending at 5:15 PM CST)
Note: This band of snow has produced about 2 inches of snow this afternoon with 2.5 inches of snow reported 5.1 miles north of Pillager, MN (Cass County) and 1.9 inches of snow reported 3 miles north of Brainerd, MN (Crow Wing County) per NWS Duluth snowfall reports.
18z NAM-WRF model 1-21-19
Snow will continue to develop across the area through this evening, dry air in place so it will take time for the atmosphere to saturate enough to allow the snow to reach down to the surface. Bulk of accumulating snow is expected from late this evening through the early morning hours of Tuesday. Snow is expected to taper off from W-E during the day Tuesday.
12z European ensemble model (EPS) 1-21-19
Look at this temperature anomaly map which runs from January 24 through 31 — The next few days won’t be too bad temperature wise across the Northland, but another round of arctic air moves in late this week, potentially lasting well into next week. Note: Whenever you see darker blue and purple colors on this map that is some seriously cold temperatures, possibly record breaking cold at times!
Low Temperature reports from Monday morning, January 21, 2019
5 NW Ash Lake, MN: -34 F
Crane Lake, MN: -33 F
Ely, MN: -33 F
Littlefork, MN: -31 F
Chisholm-Hibbing, MN: -29 F
Cook, MN: -27 F
4 W Grand Portage, MN: -27 F
International Falls, MN: -25 F
Aitkin, MN: -24 F
3 N Butternut, WI: -23 F
Kettle River, MN: -23 F
4 SSE South Range, WI: -21 F
Glidden, WI: -21 F
Cass Lake, MN: -20 F
7 WNW Minong, WI: -20 F
Moose Lake, MN: -20 F
Glidden, WI: -19 F
2 ENE Oliver, WI: -19 F
Barnes, WI: -18 F
Superior Airport: -17 F
2 WNW Duluth, MN: -15 F
Weather Synopsis for Northeast Minnesota and Northwest Wisconsin
Clouds have been increasing throughout the day as we get rid of the arctic air and replace it with a somewhat milder airmass as low pressure approaches from the west with southerly winds ahead of that low helping to kick out the arctic air. Highs today ranged from around 5 to 15 above zero! Warm air advection on a 40 knot southerly low level jet is causing the 850mb temperatures to rise this afternoon, they range from -10 to -14C across northeast Minnesota and northwest Wisconsin.
The air is dry which isn’t a surprise after a few days in the freezer, so it is taking some time for the atmosphere to saturate, but this has been occurring this afternoon across western-southern sections of the area where light snow has broken out as seen in observations from Brainerd, Aitkin, Grand Rapids, Longville and Pine River where visibilities have fallen to around 1-2 miles in light snow this afternoon.
Snow tonight into Tuesday morning. As stated above, we should see higher than usual snow ratios with this event due to the cold airmass. Mean layer relative humidity values of ~90% in the DGZ along with falling 850mb temps to around -15C overnight should lead to larger snowflakes and more rapid snow accumulation overnight thru early Tuesday morning.
The snow will taper off from W-E on Tuesday as the trough extending north of a surface low over the central Plains exits off to the east.
Temperatures tonight will stay above zero across the entire area, in fact temperatures should remain fairly steady in the single digits and teens tonight with highs Tuesday in the teens, and a few locations might even make a run at 20 degrees!
Note: A few flurries or snow showers are possible across the area Wednesday afternoon-early Thursday morning as an arctic front sweeps SE through the upper Midwest. Bitterly cold temperatures return for late this week and could continue through the middle of next week. Potential for daytime highs in the teens below to single digits above zero with lows in the teens, 20s, 30s and 40s below zero in northeast Minnesota and northwest Wisconsin from late this week to the middle of next week, and periods of dangerously cold wind chills are also likely.
A couple clipper systems could also affect parts of the northern Plains and upper Midwest late this week through early next week, tracks of these systems are very uncertain at the moment, but they will have to be watched as there should be a strong baroclinic zone (Temperature gradient) on either side of the low which could help produce narrow bands of more significant snowfall. Could also see periods of easterly and northerly winds develop which could lead to some lake effect snow near Lake Superior this weekend-early next week.
Duluth, Minnesota Climate Normals for January 22
Sunrise Tuesday: 7:44 AM CST
Sunset Tuesday: 4:57 PM CST