GRAND RAPIDS, Mich. (WOOD) — It’s been a fairly tame winter so far, but all Michiganders know it’s just a matter of time before the snow comes. This weekend maybe that time.
Lately winter has been on a semi-hiatus. We’ve had 19 consecutive days with above-average temperatures and during that span temperatures have been nearly 13 degrees above average. Snow? Not much. During the past 20 days, we’ve only received a little over 6 inches with a season deficit of over a foot in Grand Rapids, Kalamazoo and 18 inches in Muskegon.
This weekend’s storm may put a significant dent in that deficit.
STORM SYSTEM STILL SETTING UP
What we know is that a significant storm is becoming more and more likely, but the details are still up in the air.
Here are the storm probabilities and possibilities as of Wednesday:
Number one is the time frame. This storm has a good chance of being a long-duration precipitation event, one that could last 36 hours or more. When that is the case, the likelihood of heavy precipitation (rain, snow, sleet etc.) along with flooding increases.
River levels across West Michigan are already at 90% for flow in conjunction with soil moisture saturation levels of over 80%. Total precipitation amounts are very impressive for this time of year. Guidance from National Weather Service suggests the potential of 2 to 3 inches of rain with this storm. That would be near record levels for this time of year.
The first stages of precipitation will break out Thursday night as a cold front stalls across and just south of Michigan.
Notice the feed of cold air coming from Canada hitting the north side of the precipitation shield.
Eventually, we’ll see the northern side of this precipitation transition to snow and freezing rain. This will likely occur later Friday night.
As lower levels continue to cool, the snow and freezing rain will expand. Slippery roads are certainly possible especially from Grand Rapids to the north by Saturday morning.
The snow and freezing rain line will likely spread south during the day Saturday, possibly creating slippery roads as far south as Kalamazoo and I-94.
Low pressure will ride up along the stationary front with a track that should wind up near southern Lake Huron Sunday morning. By that point, enough cold air should wrap in to change all precipitation over to snow sometime Sunday night.
HOW MUCH SNOW WILL WE GET?
It appears the storm will be in the process of moving out Sunday morning. The question is what it will leave behind.
In these types of storms, it’s notoriously difficult to pinpoint how much snow, and freezing rain will fall in your backyard. The switch from rain to frozen precipitation is critical, along with the track of the storm system itself.
Here’s an example of some of the model disparities that forecasters are presented. Let’s begin with snowfall. Below is the 6z snowfall forecast from the GFS or American model. The 3- to 6-inch snow line bisects Grand Rapids:
Below is the European model snow forecast for the same time period. It too has the 3- to 6-inch snow range over Grand Rapids but it has the heaviest snow displaced north of Grand Rapids as opposed to east.
That’s not a typo: This particular model shows 18 inches of snow forecast across the northern sections of the viewing area.
Look closely at the complexity of the forecast. Take Kent County for example. The European model is forecasting the possibility of 18 inches of snow in the northwest corner of Kent County, yet the southern sections may only receive 1 to 3 inches. That’s a difference of over foot in about a 30-mile distance.
This difference with freezing rain amounts is just as staggering.
If the European model is correct, that would be an historic ice event. Let’s hope it’s not.
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Besides the precipitation, we can’t forget the winds, which could gust in excess of 40 mph later Saturday though Sunday morning. This certainly would compound the issue with heavy snow and ice on trees and power lines.
The model discrepancies are vast, but as we get closer to the event things should come into better focus. So stay tuned to Storm Team 8: We will present any changes to the forecast and relay to you the inevitable watches, advisories and warnings issued by the National Weather Service.