Clipper System to Bring Snow to Upper Midwest

6:40 PM Tuesday, December 17, 2024

-Computer models have been showing a clipper system affecting parts of the northern Plains and upper Midwest Wednesday night into Thursday and this trend in the models continues today.

-Low pressure is forecast to track east-southeast out of northern Montana Wednesday evening, reaching western areas of North Dakota. Then, this low is forecast to take a dive toward the southeast, likely reaching northeast Iowa by late Thursday afternoon. It should be noted that the HRRR and RAP models are currently indicating a significantly more northern track for this low on Thursday. While this cannot be completely discounted at present, it is anticipated that these models will shift the low’s track further south in their upcoming forecasts

-Some snow is likely in much of the Northland with this system early Thursday morning through late Thursday afternoon. This snow should be quite fluffy due to the amount of cold air in place.

-In addition to the system snow, there is a chance for some lake-enhanced snow along the North Shore of Lake Superior, including in the Duluth area on Thursday, as winds will be out of the east. There should be plenty of cold air for some lake enhancement, as 850mb temperatures are forecast to range from around -12 to -15°C over Lake Superior on Thursday.

-A constraint for a major lake-enhanced snow event in the North Shore area on Thursday is the frequent change in wind direction, transitioning from east-southeast to east-northeast, then to northeast, and ultimately to north-northwest by Thursday evening. Consequently, the winds will not remain in a favorable direction for an extended period anywhere along the North Shore, which should limit excessive snow accumulations.

Duluth area: Snowfall is expected to start early on Thursday morning, between 4 AM and 7 AM, and is predicted to diminish Thursday night, between 8 PM and 11 PM.

NAM 3km model simulated radar forecast valid Midnight Thursday to Midnight Friday.

Among the 20 members that constitute the GEFS model, a greater number still indicate some snowfall rather than no snow across much of the Northland on Thursday. The task now is to fine-tune the predicted snow amounts for this system.

Winter storm watches cover parts of North Dakota and far western Minnesota from Wednesday evening through Thursday, and additional winter weather headlines will likely be issued farther south/east into parts of Minnesota over the next 24 hours.

Back to tonight for a moment, we have seen some snow in parts of southern Minnesota today as a wave moves east out of South Dakota with some scattered snow showers and flurries farther north in our area, and we expect more of the same tonight into Wednesday morning, with less than an inch of snow expected in northeast Minnesota and northwest Wisconsin.

Radar loop ends 6:12 PM Tuesday, December 17, 2024.