The GRR NWS has issued a Winter Weather Advisory for all but the US 10 counties to the north. It’s a Winter Storm Watch for the Counties that border Indiana (and that will likely be upgraded to a Winter Storm Warning. Here’s the Forecast Discussions for West Michigan and Northern Indiana. The Advisory runs from 7 pm Saturday (though many of us along and north of I-96 will through the early evening before roads get slick) to 6 am Monday morning. So, this will be a long duration event. The NWS is going for accumulations of 8-10″ for the I-94 counties, 5-8″ for Allegan, Barry, Eaton, Ingham, Ottawa, Kent, Ionia and Clinton Counties and 2-5″ for Oceana, Muskegon Newaygo, Montcalm, Mecosta, Isabella and Gratiot Counties. Accumulations of 10 inches or more are possible for the counties that border Indiana and large parts of N. Illinois, N. Indiana and N. Ohio, including the cities of Chicago, S. Bend, Fort Wayne and Cleveland. Not only will will have to deal with the snow, but temperatures will be cold enough (teens to low 20s) for the light snow to drift around in the 20-30 mph wind gusts that we’ll see. Obviously, this is going to cause some pain for those of you traveling to and from Super Bowl Parties. The Chicago NWS is going for 5-10″ of snow for NE Illinois. Here’s the Midwest Watch/Warning/Advisory Map. The heaviest snow may occur along and just south of I-80.
Now, keep in mind that for wet, heavy snow – about 8″ of snow = one inch of water. For dry, light snow – apt to fall at cooler temperatures, the ratio increases to 15″ or even 20″ of snow per one inch of water. The overnight European model gives G.R. 0.43″ of precipitation. So, at 10 to 1 that would be equivilant to 4.3″ of snow. At a 15 to one ratio, that’s about 6.4″ of snow (and that’s more likely with this storm). For Big Rapids, the European model gives Big Rapids 0.13″ of precipitation – so maybe 2″ (though even 2″ with 20 mph winds is going to cause some drifting problems. Now, for Sturgis at the Indiana border – it gives 1.02″ of precipitation. At 15-1 snow to water, that would be over 15″ of snow – a very major snowstorm. Storms like that are rare, so just based on climatology, you’d be tempted to cut that total down a little bit. But, a foot of snow with 30 mph wind gusts could easily bring 2-3 foot drifts and some major travel problems.
The NAM (caribou) overnight model snowfall totals: Grand Rapids 5.6″, Kalamazoo 15.2″ (!!!), Big Rapids 2.7″, Cadillac 0.2″, S. Haven 10.5″, Holland 7.8″, Muskegon 3.5″, Lansing 7.3″, Jackson 13.9″, Mt. Pleasant (aka “snow desert”) 3.8″, Pontiac 9.2″, Ludington 2.5″.
The GFS (caribou) overnight model snowfall totals: Grand Rapids 4.9″, Kalamazoo 9.8″, Big Rapids 2.7″, Cadillac 2.4″, Muskegon 3.5″, Lansing 5.2″ Jackson 9.2″, Mt. Pleasant 3.9″, Pontiac 4.0″, Ludington 2.5″.