DETROIT (WWJ/AP) – First comes more snow to Michigan, then the freeze. Well, a deeper freeze.

The National Weather Service has issued a Winter Storm Warning, in effect from Saturday evening through 10 p.m. Sunday for southeastern Michigan.

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Forecasters say much of the southern portion of the state will be blanketed with anywhere from six inches to nearly a foot of snow by late Sunday.

Accumulating snow will begin late Saturday and bring around an inch of snow by early Sunday morning. The main surge of heavier snow is then expected on Sunday afternoon with additional accumulations of 5 to 8 inches.

Meteorologist Dan Thompson of the NWS office in Oakland County’s White Lake Township said a temperature plunge will immediately follow the snowfall, sending the thermometer to well below zero on Monday night.

The temperature plunge is being blamed on a so-called polar vortex, which is caused by a counterclockwise-rotating pool of cold, dense air.

A relative warm-up comes later in the week, when temperatures will reach the high 20s.

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Here’s the local forecast from the CBS Detroit weather team:

Sunday — Snow of varying rates, accumulating an additional 6-10 inches. Winds SE at 10 to 15 mph. High 29F.

Sunday Night — Snow in the evening, accumulating 1-3 inches; storm total snowfall 8-12 inches. Cloudy and frigid.  Winds NNW at 15 to 25 mph. Low 2F.

Monday — Extreme cold. Mostly cloudy and windy with a couple of snow showers.  Winds W at 15 to 25 mph. High 2F.
Monday Night — Partly cloudy, breezy with the temperature breaking the record low temperature.  Winds SW at 15 to 25 mph. Low -9F.

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