Two periods of rain will really add up the moisture amounts over the next two days. Part of southern Lower Michigan should have around one inch of total rain, which is a heavy amount of rain during winter.
One note to begin with is we shouldn’t have any freezing rain with these two rains. Temperatures won’t go any lower than 33 degrees and most of the time range between 33 degrees and 37 degrees. Those temperatures are warm enough to avoid freezing rain.
Here is the surface weather forecast from this morning to noon Friday. You can clearly see the two waves of rainfall. This forecast shows an area of mixed rain and snow developing around Saginaw Bay Thursday night. You might see some wet flakes but no accumulation.
The first wave of rain comes through the southern two-thirds of Lower Michigan today with what I would call light rain. Total rainfall amounts will be around one-quarter of an inch. The rain should happen at times all day in the form of off and on showers. This first rain will make it as far north as the south side of the Traverse City area.
The second wave of rain will be heavier and turn all of Lower Michigan wet. The Upper Peninsula only gets a few light showers out of this second rain. Southeast Lower Michigan and especially the Thumb will get into the heaviest rain which should total more than one-half inch Thursday night and Friday morning.
When we add the two rains up there will be a lot of moisture for a winter rain event.
Here’s the total rainfall forecast from this morning through Friday afternoon. The yellow and orange shaded areas will have at least three-quarters of an inch of rain to over one inch. The orange area in the Thumb, Flint area and the northeast Detroit area are projected to have between one inch and one-and-a-quarter inches of rain by noon Friday. For every couple of rows of counties we go north in Michigan you will have one-quarter inch less rain. Traverse City and northward is only looking at one-tenth of an inch of rain.
A closer look at southern Michigan shows the entire area and all of the big cities from Grand Rapids, Saginaw, Bay City and points southeast will have a total of over three-quarters of an inch of rain in today’s rain and the Thursday night/Friday rain. This also includes Ann Arbor, Detroit, Jackson, Lansing, Kalamazoo and Battle Creek. Muskegon should stay around one-half inch of rain total.
The rain will occur with temperatures just above freezing. This will cause a lot of snow to melt. Get ready for dense fog at night and early morning. This fog pattern should happen tonight, Thursday night and Friday night. A change to a north wind Saturday night may take out the high moisture content in the air and end the foggy stretch.