Updated Snowfall Projections for Winter Storm

Posted at 10:28 AM, Dec 19, 2012
and last updated 2012-12-19 10:28:12-05

GRAND RAPIDS, Mich — As a significant winter storm continues to develop to our southwest, it appears that the band of heaviest snow will stay generally north of the FOX 17 viewing area.  Still, significant effects on travel are expected around West Michigan during the day Friday.

As the FOX 17 meteorologists have discussed in previous posts (see Tuesday evening, Tuesday morning, Monday evening), the basics of the forecast have become pretty clear: a mix of rain and snow will transition to mainly rain Thursday, then back to snow Thursday night before winding down Friday.

There are two primary questions yet to be answered that will help determine our final snowfall amounts:

  • Where will the rain/snow line stop its progress northward during the day Thursday?
  • How much longer will the storm hang around once the rain changes to snow Thursday night?

Currently, forecast model projections are fairly consistent in telling us that the rain/snow line will get north of Grand Rapids and Muskegon Thursday.  It’s likely, then, that the heaviest snow will fall in areas north of U.S. 10.  Parts of northern lower Michigan may easily see up to a foot of accumulation Thursday into Friday.  However, there will also be some areas in Oceana, Newaygo, and Mecosta counties that end up with totals of six inches or more.

For the majority of West Michigan, however, rain will make up a large portion of the precipitation from this storm.  That cold, wind-driven rain will persist through much of Thursday and into Thursday evening after some areas see minor slushy accumulations of snow early Thursday morning.

A burst of heavy snow Thursday night into Friday morning will make up the majority of the accumulation for most of the area.  Current forecasts keep that snow around until around midday Friday, with an average of about two to four inches of snowfall.

The other wild card in that forecast is lake-effect and lake-enhanced snow, which could add another inch or two to totals west of U.S. 131.  That snow will be blowing and drifting Friday as winds gust to 50 miles per hour or more.  The southwest corner of the state will be most affected by snow coming off Lake Michigan.

The National Weather Service has issued Winter Storm Watches (which will likely be changed or upgraded to warnings eventually) along the lakeshore and for the northern section of the FOX 17 viewing area.  It should be noted that this storm does not meet the traditional criteria for a winter storm in many of these locations (six inches of snow or more in 12 hours, or eight inches in 24 hours).  However, the combination of snow, falling temperatures, and extremely strong winds will create hazardous conditions for much of the region Thursday night and Friday.

Because the main thrust of snow is still about 36 hours away, we will continue to refine the snowfall forecast.  Check out the latest information, plus interactive radar, on the Weather page.