A medium-scale discussion was posted by the Storm Prediction Center, which is NOAA’s branch for severe weather forecasting. The discussion highlights southeastern Lower Michigan for the possibility of snowfall rates greater than 1 inch this afternoon in the purple scalloped area. Detroit, Ann Arbor, Jackson, Hillsdale and Monroe are all within the highlighted area of possible heavy snowfall rates.
The discussion reads: “Moderate to heavy snow expected to continue northeast across central and northern IN, extreme northwest OH and extreme southeast Lower Michigan until mid-afternoon. A few instances of snowfall rates over 1 inch/hr are possible in the heaviest bands.
If you want to be brave enough for a technical weather discussion (I’ll add some explanation in plain English), they also state, “A surface low is centered around the IN/KY boundary and is about to continue to drift northeast towards Lake Ontario throughout the day while intensifying. Strong warm air/surface moisture advection up to 700 mb (about 15,000 ft) will continue to supply relatively rich moisture to the dendritic growth zone (where snowflakes become large and accumulate more easily). The upwelling of this moisture while wrapping around the surface low should continue to support at least moderate to occasional episodes of heavy snowfall up to 20Z (3 pm) northwest of the mid-level dry slot. The heaviest snow, including brief instances of snowfall rates in excess of 1 inch/hr, will most likely be where the 700 mb frontogenesis and associated lift will be strongest. The latest mesoanalysis suggests that this corridor is located from central to northern IN/extreme northwest OH and extreme southeast lower MI.
In other words, an area from Ann Arbor to Detroit and into far southeast Lower Michigan could have large, rapidly accumulating snowflakes for a few hours this afternoon. Visibility will be reduced, snow may pile up faster than plows can remove it, and driving will be hazardous.
Don’t drive somewhere until tomorrow if you don’t have to go today.