It's a tricky forecast to say the least, but rest assured, Sunday and Monday are going to be interesting days weatherwise. A low pressure system is rapidly deepening over the Central Plains and making its way directly toward the U.P.
For now, Upper Michigan is experiencing a strong southerly flow that is bringing very warm and humid conditions to the Great Lakes area. Highs for us Sunday should be in the low to mid 30s. Skies will be overcast.
The track of this deepening low pressure system is looking to head directly over the U.P. late this evening. This means heavy system-related snowfall, but due to the mild temeperatures ahead of the low, precipitation type could be complicated.
Low temperatures Sunday night will be in the 10s but a bit warmer east near Lake Michigan. With warmer air aloft, precipitation could easily be a snow and rain mix or freezing rain. Road conditions will become very hazardous.
The National Weather Service has issued a variety of Winter Weather Watches and Advisories to address the hazardous conditions to begin Sunday night and lasting mainly through Monday night.
Earliest snowfall should begin around 6 or 7 p.m. in the west and work its way east overnight. The heaviest hit areas will be the central and northwestern counties. The heaviest snowfall should be Monday in the daytime.
Snow will last through Tuesday as it turns into lake effect snow north. Conditions will be windy as the low moves away making blowing snow a concern.
Total accumulations from Sunday night through Tuesday: Marquette and Baraga Counties should see 6", similar amounts south towards Iron Mountain or maybe a bit less, around 8" in the Keweenaw and Houghton areas, and only a few inches east of Marquette County.
Note that the areas east of Marquette County will still see plenty of precipitation, but less snow.
Monday's highs will be warmer than Sunday in the 30s but with lows dropping down quickly to around 20 and colder.
Down south:
The south wind associated with the oncoming low has completely opened up the Gulf of Mexico and brought even warmer and wetter conditions down south. As the low passes, it will really set the stage for severe weather. The warm and moist air is becoming very unstable and just needs a forcing to get going.
That forcing will be a strengthening cold front. Severe weather should break out in the form of an intense squall line capable of producing strong tornadoes, hail, and strong straight line winds. Severe weather initiation down south is expected to begin this evening, focused around Mississippi north through far southern Illinois.