Freshening the snow cover; another frigid weekend

A fairly weak weather disturbance is headed our way to add fresh snow to the landscape. Light snow will break out in southwestern Minnesota Wednesday evening and then spread northeastward. Snow is likely to reach the Twin Cities after midnight and continue at least through Thursday morning. The snowfall should exit the state from west to east and end in eastern Minnesota during the afternoon.

Here is where weather radar is showing snow falling late this afternoon:

Dec 27 - radar
Weather radar shortly after 5:30 p.m. Wednesday. Sioux Falls National Weather Service

The air mass is quite cold and dry, so the snow will be light and fluffy. The ratio of snow to its liquid water content should be about 20:1, so with just a little more than a tenth of an inch of liquid forecast I would expect most snowfalls to be around 2 to 3 inches. Some spots in central Minnesota might see a bit more than 3 inches. And some areas near Canada and also in southeastern Minnesota near Iowa might get closer to just an inch.

Thursday's high temperatures will be milder but still well below normal. Highs should range from around zero in the northeast to actual low and mid teens above zero in the south. The Twin Cities should reach about 11 in the afternoon. But it will be one-day wonder.

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Bitter cold again for the weekend

Colder air will begin to return on Friday. By the weekend we will be back in the deep freeze.

Low temperatures on Saturday, Sunday and Monday will plunge into the 30s below zero in northwestern Minnesota. Meanwhile, we will have widespread 20s below zero in much of the state and teens below zero in the south. The Twin Cities should chill to around 13 below all three days.

Dec 27 - Sun min temps
Forecast low temperatures for Sunday morning. NOAA/Weather Prediction Center

High temperatures on both Saturday and Sunday are likely to remain sub-zero for nearly all of Minnesota as we close out 2017.

Monday afternoon's temperatures should be several degrees warmer than Sunday's as a thermal moderation begins.

By next Wednesday, the morning low temperatures will be much less dangerous:

Dec 27 - Wed min temps
Forecast minimum temperatures for next Wednesday. NOAA/Weather Prediction Center

We could even get back to near-normal temperatures by the end of next week, if only temporarily.

The rest of the snow season

Here is the official forecast for departures from normal precipitation for the period January through March:

Dec 27 - 3 month precip departure outlook
Forecast departures from normal precipitation for January through March. NOAA/Climate Prediction Center

The main messages are for more precipitation than normal likely from the mid-Mississippi and Ohio River Valleys to the Lower Great Lakes, and rather dry weather for Florida, the Gulf Coast and a large area of the Southwest.

We might trend toward slightly snowier than usual if the forecast works out. Keep in mind that precipitation outlooks, which rely on dynamic interactions, are much less reliable than temperature outlooks which rely mainly on air mass characteristics.