Wind Chill Advisory in effect for SE Michigan

Plus, an update about our weekend storm


DETROIT – Clear skies, very dry air, light wind, and a fresh, deep snowpack overnight will allow temperatures to absolutely crater.

Warmest readings in our Urban Heat Island should still fall to at least -10°, while those of you in the typically colder suburbs should plummet to between -15° and -20°. The coldest spots may even fall to between -20° and -24°.

Fortunately, with nearly calm air, we won't have a wind chill to deal with, which will certainly raise a question for some of you: If there's no wind chill, why did The National Weather Service issue a Wind Chill Advisory for tonight? The answer is quite simple: temperatures tonight without the wind will fall to levels that they would warn you about if it was a wind chill temperature. Since there is no official warning or advisory product for just the cold temperatures we'll see tonight, they issued the Wind Chill Advisory. Please make sure that you are dressed appropriately if you expect to have any prolonged exposure to this bitter cold. And also remember to bring the pets in -- this is dangerous weather for them, too.

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Bitter cold sunshine will start our Friday, and we should keep the sun through the morning. Clouds will then tend to increase during the afternoon. Highs around 10° -- perhaps even a bit warmer -- but a developing south-southwest wind at 10-15 mph by afternoon will keep wind chills near or below zero.

Light snow develops Friday night. Lows in the single numbers will actually be set Friday evening, as temperatures rise into the low teens by Saturday morning.

Light snow continues on Saturday, with 1" to 2" of general accumulation across the area. Those of you in southern Lenawee and Monroe Counties need to keep an eye out for slightly more snow, as you'll be closer to another system passing to our south. And here's the best news of all: with highs reaching the upper 20s, we can actually go out and play in this snow!

OK, what about the Sunday snow storm potential I've been telling you about all week? The computer models were all over the place this week in trying to develop a forecast for this weekend's weather pattern. I'm not kidding when I say that the models literally shifted us between big storm and no storm each day this week.

Why the problem? Because the upper level system that would eventually create the storm was still way out over the Pacific. It's not until that system crosses the west coast and gets studied by our weather balloon upper air network that the models get a better handle on its structure and physics. That happened today, which is why I'm finally seeing some consistency in the models' handling of the storm.

Another problem that the models had was whether to keep two separate storm tracks across the country (a southern track and a northern track), or to phase them into a single storm track – which usually translates into a stronger storm. Today's models are maintaining separate storm tracks -- a northern track that will bring Saturday's weak system across the area, and a southern track that will bring more unwelcome winter weather across the mid-south. Had those tracks phased, then a single, stronger storm likely would have dumped a lot of snow on us on Sunday. Instead, well, read on!

Mostly cloudy Saturday night, with lows in the upper teens.

Becoming partly cloudy and breezy on Sunday. Highs in the low 20s will be set in the morning, before temperatures start falling.

Becoming mostly clear Sunday night, with lows averaging around -5°.

Mostly sunny on Monday, with highs near 10°.

Becoming partly cloudy Monday night, with sub-zero lows being set Monday evening, and temps then rising to just above zero by Tuesday morning.

Increasing clouds and becoming windy on Tuesday with some snow developing. It's way too early to try and even guess what kind of accumulation this appears to be. Highs near 20°.

Snow diminishes Tuesday night, with lows in the single numbers.

Partly cloudy and windy on Wednesday, with highs in the mid teens.

Partly cloudy Wednesday night, with lows around -6°.

Partly cloudy on Thursday, with highs in the mid teens.

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