Potential big snow: Why the forecast for Monday is worth watching

Posted at 10:30 AM, Jan 21, 2021
and last updated 2021-01-21 10:35:55-05

(WXYZ) — The potential is there for our first "big snow" of the year early next week, but right now the confidence in the forecast is low due to large discrepancies in the forecast models.

First, a weak area of low pressure is expected to track north of the Great Lakes and bring light snow to southeast Michigan Sunday and Sunday night. I'm fairly confident we'll get some snow Sunday, but I don't expect big impacts from this as there won't be much moisture to work with; maybe an inch of snow.

Then we get to a more difficult forecast for Monday. A stronger area of low pressure moves in from the southwest. Storm systems that move in from the south have more moisture, so even though this low is expected to track south of us, across the Ohio River Valley, a large band of snow on its northern edge could still cover most of lower Michigan. The strength of the storm system, how far north it tracks, and the timing of the day it arrives are all key in determining this forecast.

European Model Forecast
GFS Forecast Model

The European model brings us heavy snowfall Monday night; suggesting 4"+ of snow around Metro Detroit. Keep in mind if the moisture arrives earlier in the day, this could become a mix of rain in our southern counties.

The GFS model solutions indicate a northeast wind across the Great Lakes suppressing any snow from even moving this far north, meaning we don't see any snow at all Monday. The Canadian GEM model is in more alignment with the American GFS model.

Snow-lovers are crossing their fingers for this storm system to take the right path. Others are hoping they won't have anything to shovel Tuesday morning. I'm leaning slightly toward the "no snow" outcome for Monday, but as I said, confidence is low right now.

So pay attention to the forecast for Monday as it will change over the next couple of days. The models typically become in better agreement 2 or 3 days out of an event. This "wave" in the atmosphere will move over the west coast Friday into Saturday, and we'll have more of analysis then.