Winter storm headed toward the Great Lakes

How will it affect southeast Michigan?


DETROIT – I guess I don’t need computer models anymore.  All I have to do is wait for the e-mails and tweets to start coming in with people asking about a massive storm that some alarmist weather source told them about, and I’ll know that some sort of weather event is on the horizon. 

Seriously -- somebody on Sunday actually tweeted me asking about the “3-5 inches” of snow we’d be getting on Wednesday.  I wasn’t expecting anything of that nature, except possibly for the farthest northern reaches of our area, and my expectations have not changed since then.

Alright, here’s what I’m thinking about the storm of the next two days, and keep in mind that there are still some very significant differences among the suite of computer models.

The GFS advertises a farther north, warmer track to the approaching low pressure area.

The ECMWF shows a farther south and colder solution.

The NAM is right in the middle and, right now, is the favored model today (channeling my inner Goldilocks today).  Based upon this, I think we’re talking about a rain event for most of us. Only those of you well north of I-69 need to worry about significant wintry precipitation.

My RPM has a similar output to the NAM today, so I’ve posted below a series of maps showing the timing of things.

After a few light showers tonight, with lows in the mid 40s (7° Celsius for our Canadian friends), the first half of our Wednesday features a few light showers – especially across the northern half of our area.

Rain should increase through the day, with snow breaking out over especially the northern half of Sanilac County. Remember my caveat from above:  there is still some big differences among the computer models, and only the slightest shift north or south in the storm track will dramatically change the location of that snow area.

As you look at the maps through Wednesday evening, notice that the orientation of the rain/snow line in Sanilac County doesn’t move much…that’s why the track of the low is so important.  Those of you who get snow tomorrow will probably stay snow for a long period of time, allowing for a few inches of wet snow accumulation, so that’s why a small shift north or south will make such a big difference.  

For the rest of us, this is going to be a long-term, steady rainfall, with an inch of total rain certainly attainable.

Temperatures Wednesday will also be on the crazy side, because a stationary front (brilliantly called that because it isn’t moving much) may be sitting across our southern counties.

South of the front, you’ll be in the 50s (12° Celsius); north of the front you’ll just hold in the mid 40s (8° Celsius)…making for a miserably cold rain.

Rain continues Wednesday night and, if the RPM and NAM are correct, even you folks in Sanilac County may see a changeover to rain, with steady temperatures (whatever you end the afternoon with Wednesday will probably be your overnight temperature, too).

Rain persists through at least the first half of the day Thursday, and possibly through the afternoon.  Highs in the mid 50s (13° Celsius), as most of us should, at least briefly, see that warm front move north.  It’s going to be a windy day, too.

Mostly cloudy Thursday night…perhaps becoming partly cloudy late, with lows dropping back into the upper 20s (-2° Celsius).

Partly cloudy on Friday, with highs in the low to mid 40s (6° Celsius).

Mostly clear Friday night, with lows in the upper 20s (-2° Celsius).

Partly cloudy on Saturday, with highs in the mid 50s (12° Celsius).

Rain chances then return on Sunday, with highs in the low 50s (11° Celsius).

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