Big weekend storm could bring heavy snow and rain

Posted at 10:12 AM, Dec 13, 2016
and last updated 2016-12-13 10:13:07-05

WEST MICHIGAN –After an Arctic blast of air with temperatures in the teens, wind chills between -5 to -15 below zero, and some accumulating lake effect snow Wednesday and Thursday, our attention turns to another strong developing low pressure system forming over the Rockies that may start impacting us by Friday night.

Typically what happens with these lows when they track over the Rockies is the column of air gets stretched (vertically) and the low actually strengthens or undergoes what meteorologists refer to as cyclogenesis. That will occur with this upcoming weekend system as it tracks in to the Great Lakes. The current track has the low moving over/near Chicago on Saturday. This track would wrap a significant amount of warm air in to the system (from the south) and change snow to rain by mid-late morning Saturday. Of course if the system tracks further south/east, Michigan will stay in the colder sector (north of the low) and we’ll see primarily snow.

Take a look at one of our computer forecast models. The image below is the location of the low at 6 PM on Friday. Probably still dry at that time, but the map shows the colors are still quite cold enough for just plain snow as it develops Friday night. Note the blues over the area.


The next image below shows the same forecast model valid at 6 PM Saturday. Look specifically at the position of the storm center (or low) as well as the colors on the map. On this track, the low would pull in enough warm air to change any snow to rain…especially from Grand Rapids southward. In fact, temperatures along the Michigan/Indiana border could approach 40 or better. This same forecast model prints out about 5″ to 7″ of snow for Grand Rapids southward, before changing to all rain and dropping another one inch or more in liquid precipitation. If this is correct, we could be looking at flooding issues, so make sure to stay up on later forecasts.


Suffice to say a major storm system will head our way and impact the Great Lakes, but precipitation type will be contingent on the exact track of the storm. That’s the way it looks now. Get the complete West Michigan forecast at