DETROIT – Here we go: Our attention is turning to the next major weather system expected to arrive on Friday afternoon. In response, we’re declaring Friday, Jan. 11 a 4Warn Weather Alert Day.
Prepare for our first significant snow of the season, whipping winds, and brutal wind chills this weekend.
A winter storm watch has been issued from 10 a.m. Friday-10 a.m. Saturday for the far northwest suburbs from Livingston County stretching up to Sanilac County. The heart of Metro Detroit is not currently under a watch or advisory yet, but I would expect that to be issued sometime Thursday.
Snow totals - projections
We have confidence that the precipitation will initially arrive as snow on Friday. The peak intensity of the precipitation is expected during the late afternoon and evening hours Friday.
There still remains some uncertainty about the northward progression of the rain/snow line, and where exactly it will fall. (I anticipate some more fine tuning to the forecast over the next 24-36 hours as we get a better grasp of that brief pocket of warm air Friday night.)
If the rain/snow line falls and tracks more north, we’ll see warmer temperatures in Southeast Michigan -- which will significantly limit the amount of snowfall we see. As of Thursday morning, this scenario seems to be the most probable for Metro Detroit.
With this said, it still is possible that the Metro Detroit area could receive 2-6 inches of snow as more snow builds in before sunrise on Saturday. (Areas closer to Monroe should see lesser amounts of snow because they’ll likely get a bit more rain.)
The Thumb region and our northwest communities that are under the winter storm watch are more likely to see 6-8 inches of snow by Saturday.
We will see an initial accumulation with higher-intensity rates Friday afternoon and early evening.
Rain could cut down on some of that accumulation Friday night before we bookend the system with lighter-intensity snowfall on Saturday as colder air works its way in. So, that leads us to the timing ...
Snowfall timing
Snow increases in coverage and intensity Friday afternoon. We start to see the onset of snow move north into our southern counties as early as midday.
This heavy, wet snow will move north toward M-59 by 3 p.m. Friday. Peak snowfall rates are expected Friday afternoon and evening and could potentially reach an inch per hour.
All of Southeast Michigan will be blanketed with heavy snow by 5 p.m. This will impact the Friday evening commute.
The rain/snow line will bring a transition to rain for southern portions of the area by Friday evening, reaching the I-94 corridor by 8 p.m.
The rain/snow line will lift up toward M-59 by 10 p.m. This window of warm air should be rather limited.
It looks like a small window of dry air could possibly move in overnight behind it.
Before snow re-develops as temperatures tumble Saturday morning.
Numerous snow showers with additional snowfall will be likely Saturday as colder air moves in.
Whipping winds
Winds will pick up with gusts up to 45-55 mph on Saturday. This could meet the criteria for a wind advisory. One has not been issued by the National Weather Service yet, but when you pair that type of wind with heavy snow, we could see whiteout conditions with blowing and drifting snow.
I also have concerns about power outages, especially as any wet/rainy precipitation freezes over early Saturday.
Arctic air moving in
Behind this system will be an arctic blast of air. Subzero wind chills on Sunday will last into early next week.