St. Cloud, MN Weather Forecast

Two Storms: Wednesday Night-Thursday and Friday Night-Saturday

I will spend most of this discussion talking about the two potential upcoming storms, one from Wednesday night through Thursday, and the other late Friday into Friday night and perhaps Saturday. 

Storm 1 Will Produce Both Accumulating Snow and Ice (Confidence 3 of 10)

The forecast for the first storm is now more consistent than it was yesterday. Central and southern Minnesota appear to get the bulk of the significant precipitation (see Days 2-3 on the NWS WPC quantitative precipitation forecast). The ground temperatures appear cold enough to support frozen precipitation; however, a warm layer at 5,000 to 10,000 feet above the ground mean that the frozen precipitation will fall as wet snow at the northern end of the heavy precipitation with the potential for significant ice accumulation to the south. The mixed precipitation type and the location of the initial storm still in the eastern Pacific (see College of DuPage North America water vapor loop) and out of the North American upper air observing network means that my forecast confidence is still rather low (3 of 10).

At this point, it appears that central Minnesota will have the best shot for the wet snow to accumulate mainly Wednesday night, although that snow could linger into part of Thursday. St. Cloud and Alexandria and points north will have the best chance for shovelable wet snow (potential between 2 and 5 inches) during this period. There is a chance for a period of mainly freezing rain on Thursday morning, with the better chance between St. Cloud, Willmar, and the Twin Cities, but any ice accumulation will depend on the temperature. The precipitation will begin over the Minnesota River Valley and the Twin Cities as snow, but that warm layer of air aloft will quickly produce a mixed bag of snow, sleet, and freezing rain. So, there is the potential of a couple of inches of wet snow or slush with the chance for ice accumulation late Wednesday night into Thursday morning as long as temperatures remain near freezing. I would favor the ground temperature getting a little above freezing on Thursday, in the Twin Cities and Mankato, so there could be a period of all rain with some melting. However, any forecast including mixed precipitation has a high degree of uncertainty. And, that also includes the potential that the precipitation band could move north or south and that showers and thunderstorms in the southern end of the main rainfall band (over Iowa and southward; see NWS Storm Prediction Center Day 2 and Day 3 convective outlooks) could steer to the east of the area favored for frozen precipitation. 

Storm 2: Snow, Especially to North??? Major Rain to South??? Light Mixed Precipitation Here???

A second storm to the south of Alaska (see Pacific mid-troposphere water vapor loop from Colorado State satellite slider) is forecast to follow the first storm, but take a more northern track into the Pacific Northwest, reaching the Dakotas by Friday evening and moving across Minnesota early Saturday. That system won't pull as much moisture into Minnesota as the Wednesday night-Thursday one, but it will still have the potential for significant frozen precipitation (see Days 4-5 on the NWS WPC quantitative precipitation forecast). The best chance for accumulating snow appears to be in the Dakotas with an uncertain potential in Minnesota (see dark green on Days 4-5 of the NWS WPC Days 4-7 winter weather outlook). That could be enough snow to shovel. There is the potential for a major dry slot between the heavier precipitation to the south and east of St. Cloud, much of which would be rain, and the potential snow on the northwestern flank of the storm, so parts of Minnesota could get little precipitation. However, the track of the storm is still moving by half a state per run, so I can't rule out a chance for at least some frozen precipitation in Minnesota. While southern Minnesota and points south should see mostly rain, there is still the possibility that frozen precipitation, outside of the heaviest snowfall, could end up as a mixture of wet snow sleet and freezing rain. My confidence in the second storm forecast is 2 of 10.

Beyond the Storms...

I won't say much for the period after the storms, except that it appears that we could get out of this wet pattern from Sunday into early next week with seasonable or cooler than average temperatures.