The forecast has been unfolding just as expected so far.
A low-pressure system was over southeast Minnesota early this afternoon and is expected to move northeast through Wednesday.
Temperatures higher up in the atmosphere are continuing to drop across northeast Minnesota and northwest Wisconsin this afternoon, with the 850mb freezing line stretching from around Sandstone MN to Mercer WI, and it’s expected to push farther south through tonight.
Surface temperatures will gradually respond to the colder air above, but it will take some time before they drop enough for snow to develop near Lake Superior. As of 1 PM, temperatures there are still in the upper 30s, a few degrees cooler than the lower 40s recorded earlier this morning.
A strong 500mb low over eastern South Dakota, paired with an upper-level trough and significant 12-hour height falls of 120 to 150 meters across the northern Plains, is expected to shift into the upper Midwest tonight.
This afternoon, some of the heaviest precipitation is happening near this upper-level system, where strong lift is clearly shown by the orange and red colors on the map.
This afternoon, rain and snow will persist across parts of the Northland.
Rain is most likely near Lake Superior, while the rest of the area can expect snow or a mix of rain and snow.
Any rain or mixed precipitation will then shift over to snow from west to east this evening, and the snow will continue overnight into Wednesday; although the snow will diminish from west to east, except along the south shore of Lake Superior in northern Wisconsin, where lake effect snow persists through the day Wednesday.
In the Duluth area, the switch from rain to snow below the hill is expected to happen between roughly 4 and 7 PM today.
NAM-Nest model precipitation type forecast through 7 PM Wednesday.
Snow – blue
Rain – green
I’ll provide another update this afternoon, including a refreshed snowfall map.
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