A mesoscale discussion has issued by the Storm Prediction Center, which is NOAA’s branch for severe weather forecasting. The discussion highlights southeast Lower Michigan for the possibility of 1-inch plus snowfall rates this afternoon inside the purple scalloped area. Detroit, Ann Arbor, Jackson, Hillsdale and Monroe are all in the highlighted area of possible heavy snow rates.
The discussion reads, “Moderate to heavy snow should continue northeast across central and northern IN, extreme northwest OH, and far southeast Lower Michigan into the mid-afternoon hours. A few instances of 1+ inch/hr snowfall rates are possible in the heavier bands.”
If you want the guts of a technical weather discussion (I’ll add some plain English explainers), they also state, “A surface low is centered around the IN/KY border and is poised to continue drifting northeast toward Lake Ontario through the day while also intensifying. Strong surface to 700 mb(about 15,000 feet up) warm-air/moisture advection will continue to feed relatively rich moisture to the dendritic growth zone(where the snowflakes become big and pile up easier). Upglide of this moisture while wrapping around the surface low should continue to foster at least moderate to occasional bouts of heavy snow through 20Z(3 p.m.) northwest of the mid-level dry slot. The heaviest snow, including brief instances of 1+ inch/hr snowfall rates will be most likely where 700 mb frontogenesis and associated lift will be strongest. Latest mesoanalysis suggests that this corridor is situated across central into northern IN/extreme northwest OH and far southeast lower MI.”
In other words, an area from Ann Arbor to Detroit and into far southeast Lower Michigan could have big snowflakes that pile up quickly for a few hours this afternoon. Visibility will be reduced, snow could pile up quicker than plows can remove, and driving will be dangerous.
Hold off on driving somewhere until tomorrow if you don’t absolutely have to go there today.