U.S. faces extreme cold blast, stormy weather in week ahead

Blizzard conditions are even possible early this week in the Dakotas and parts of Minnesota.

To the south and southeast of the wintry weather, a pulse of warm air surging ahead of the cold air will trigger heavy rain and severe thunderstorms in parts of the South, Tennessee Valley and Southeast. Some areas could see flooding and damaging winds, and a few tornadoes cannot be ruled out.

Not until the weekend will the Lower 48 see a pause from the extreme weather. And, even then, it will be much chillier than normal over much of the country as winter refuses to give into spring.

The frigid air, set to enter the northern Plains and Upper Midwest on Monday and Monday night, will bring temperatures about 20 to 40 degrees below normal from Montana through the Southern Plains. In some places, the cold could threaten records, according to the National Weather Service.

Single-digit and subzero high temperatures are forecast across much of Montana, Wyoming and the Dakotas on Tuesday with lows of minus-15 to minus-20. Wind chills could dip as low as minus-40.

That cold will penetrate as far south as central and northern Texas by Wednesday. Subfreezing highs are forecast to reach as far south as the Texas Panhandle.

A second, reinforcing blast of cold will dive through the northern Plains on Thursday into Friday. Unlike the first blast, it will penetrate somewhat farther east, spilling toward the Ohio Valley, northern Mid-Atlantic and Northeast. That will set the stage for a mix of wintry precipitation in these areas as a storm system rides up the Arctic front pressing eastward.

An extended period of wind-driven snow is forecast in parts of Montana, the Dakotas, Minnesota and the northern Great Lakes through Tuesday night. Winter storm warnings and winter weather advisories cover a large part of this area.

“Snowfall rates will likely exceed 1″/hr at times which when combined with increasing wind may produce near blizzard conditions with considerable blowing and drifting,” wrote the National Weather Service. “Travel is discouraged.”

Some of the heaviest snow is predicted just north of Minneapolis, where up to a foot could fall. Minneapolis is under a winter storm warning through Tuesday, with 4 to 8 inches predicted, which, combined with winds of 20 to 25 mph, is expected to limit visibility.

Just to the south and east of where snow is forecast, in a zone from eastern Iowa through Milwaukee and into northern Michigan, a mix of sleet and freezing rain is forecast to produce icy conditions. Milwaukee is under a winter weather advisory for ice accumulation from 11 p.m. Monday to 6 p.m. Tuesday.

A second storm will develop on Wednesday as the second pulse of Arctic air arrives in the central United States. While details still need to come into focus as to the exact location, it could produce a swath of icy precipitation from parts of Oklahoma through southern Ohio into Wednesday night.

By Thursday, icy precipitation could develop in northern Maryland, Pennsylvania and southern New York.

Mostly snow is probable to the north of the icy zone, probably stretching from northern Oklahoma, through St. Louis and toward Columbus and Cleveland on Wednesday into Thursday. By Thursday night and Friday, substantial snow will become possible from through much of the Northeast north of southern New York State.

Heavy rain and severe storms

With mild air surging north ahead of the Arctic blast, heavy thunderstorms could develop Monday in parts of the southern Plains and Midwest from northern Texas to southern Missouri. These areas, which include Oklahoma City and Springfield, Mo., are in an elevated risk zone for severe weather.

“Severe thunderstorms will be possible mainly this evening and overnight, in a corridor from north Texas to the Ozarks and vicinity,” the Weather Service’s Storm Prediction Center writes. “Damaging winds, hail, and a few tornadoes are possible.”

This risk zone will shift east on Tuesday, stretch through eastern Arkansas, much of Mississippi, southeast Missouri, southern Illinois, and western Kentucky and Tennessee.

The potential for heavy rain also means the possibility of flooding Monday and Tuesday. On Monday and Monday night, the zone at greatest risk of flooding spans from eastern Oklahoma through southern Illinois. That area shifts toward Kentucky, Tennessee and northern Alabama from Tuesday into Wednesday.

The threat of flooding may increase in the Tennessee Valley, in particular, on Thursday and Friday, as the week’s second storm system brings the potential for more heavy rainfall. The National Weather Service predicts five-day rainfall totals of 3 to 6 inches in this zone, and locally higher amounts cannot be ruled out.