A NAM model simulation of precipitation type and intensity as the system progresses eastward. (WeatherBell)

Much of the Midwest and the Ohio Valley are in line for a round of snow this week, and this will be the prelude to the coldest air of the season for some.

The storm that will help drive this cold air southeastward is still forming, but its components are already contributing to blizzard conditions in the Dakotas. Despite dropping hardly any snow, its instigating energy is causing ferocious blizzard conditions Wednesday. Strong winds have whipped up much of the already-fallen powder snowfall, cutting visibility to near zero and resulting in a “ground blizzard.”


Predicted 24-hour temperature change between Wednesday and Thursday mornings, from the National Weather Service. Communities in the Upper Midwest and Corn Belt could wake up Thursday some 40 degrees colder than Wednesday. (WeatherBell)

Grand Forks, N.D., experienced blizzard conditions from 2 a.m. Wednesday through at least sunrise. Visibility was below a quarter mile during this period, with winds gusting upward of 50 mph. A gust of 58 mph occurred shortly before 4 a.m. Riding those winds is a bone-chilling air mass sweeping into the region, dropping temperatures from near 30 degrees to minus-9 in just six hours.

Interstate 29 is closed from Fargo, N.D., to the Canadian border.

Once the cold air sweeps across the northern Plains and Great Lakes on Thursday, temperatures could flirt with zero in some areas, with wind chills plunging temperatures well below that.

For example, the temperature in Chicago could dip to zero early Thursday morning, thanks in part to a fresh blanket of snow draped across the landscape. Madison, Wis., meanwhile, may plummet to about minus-10. By Friday, much of the region will struggle to break into the teens, with temperatures more than 20 degrees below average.

The rapid temperature swings will make the upcoming cold snap especially uncomfortable, as many in parts of the Plains and Upper Midwest will awaken Thursday to temperatures that will be 25 to 40 degrees colder than they were at the same time the previous day. A similar plunge will occur in the Northeast on Friday.

The needed moisture for the snow, meanwhile, is organizing to the south over eastern Texas, adjacent parts of Arkansas and Louisiana, and the lower Mississippi Valley.

Yet another round of heavy rain is targeting waterlogged areas across the Southeast, many of which have already exceeded a half foot of precipitation for the month. That zone of low pressure will combine with the northern system and organize Wednesday, its trailing cold front bringing an isolated severe weather threat as it shuffles east toward Mississippi and Alabama.

To the north, Gulf of Mexico moisture riding up ahead of the cold front will eventually be swept northwestward into colder air, falling as snow northwest of the low’s center. By Wednesday evening, light snow will break out near Chicago and the Interstate 90 corridor between lakes Michigan and Erie. The heaviest snow may clip Detroit’s southern suburbs, but a few snow showers are still expected Thursday.


National Weather Service forecast snow totals through midmorning Friday. (WeatherBell)

The snow will then move into New York state and central and northern New England on Thursday, falling in tandem with the temperatures. Southern New England, however, is looking for a forecast that’s primarily wet — not white.

Winter weather advisories stretch from western Oklahoma through the Maine-Canada border, where a general one to three inches is possible. A few locales may end up closer to the four-or-five-inch mark, with the best odds being in central New York, where some lake enhancement is possible.


A NAM model simulation of precipitation type and intensity as the system progresses eastward. (WeatherBell)

Behind the storm system, a wintertime high pressure dome will surge south from Saskatchewan. By Friday morning, that high will unleash its Arctic blast across the Great Lakes and Midwest. Milwaukee will start its day at minus-4 on Friday, while parts of Chicago approach zero. (If Chicago falls below the 2-degree low measured on Jan. 19, it could be the city’s coldest morning of the season.)

Even Indianapolis should plunge into the single digits early Friday, on par with the forecast morning low in Detroit.


Possible low temperatures Friday morning as forecast by the National Weather Service. (WeatherBell)

New England will also endure the cold from Thursday night through the weekend, particularly in the northern areas.

This round of cold, like others this year, will be fleeting, as a return flow of air from the south introduces milder air by early next week, especially in the Northeast.

While few more brief shots of cold are possible across the Northern Tier in the coming weeks, anomalous warmth looks to continue for most as we head deeper into February.