An intense storm that unleashed howling winds and heavy snow from the Pacific Northwest to the Upper Midwest over the weekend is plowing eastward. It’s next set to bring tumbling temperatures to much of the eastern United States and a blast of wind-whipped snow downwind of the Great Lakes.
The storm is displacing a sprawling zone of high pressure that was responsible for record-breaking warmth in many areas last week. As it passes, it is bringing a stark pattern change to the middle and eastern United States, drawing a brief surge of cold air southward, with temperatures plummeting at least 20 to 30 degrees.
The storm has delivered several inches of snow from Washington’s Cascade Mountains to the northern tip of Michigan. While confined to the northernmost states, the storm has left behind a sizable stripe of accumulation in a season that has otherwise produced very little snow in the contiguous United States.
Moisture-rich winds blowing from Lake Superior toward the storm’s circulation greatly intensified snowfall in the Arrowhead of Minnesota, perhaps the region hit hardest by the cross-country storm. Blizzard conditions ensued and up to 12 to 18 inches of snow fell.
High winds and blowing snow were continuing across northern Michigan and the Upper Peninsula early Monday. Here, 8 to 12 inches could accumulate before the snow tapers off Monday night into Tuesday.
The storm was also dragging a cold front through the Ohio and Tennessee valleys into the Gulf Coast states, producing a line of heavy showers and storms. The National Weather Service’s Storm Prediction Center placed the zone from northern Louisiana to northern Alabama under a slight risk of severe thunderstorms on Monday. Early-morning storms led to at least 10 reports of damaging winds in Tennessee and spawned a likely tornado in west-central Louisiana.
Bitter-cold air pouring south
The strong northerly winds howling west of the storm will pull frigid Canadian air south into the United States. In what will probably be the coldest 48-hour period of the season yet for parts of the central and eastern United States, temperatures as much as 25 degrees below average will accompany brisk surface winds. In parts of the Northern Plains, wind chills dipped to minus-30 degrees Fahrenheit on Monday morning, and were predicted to remain below 0 degrees as far south as northern Iowa and Wisconsin even during the afternoon.
As the cold air mass spreads east and south, it will moderate some but still produce below-normal temperatures. In much of the interior Northeast, temperatures Tuesday morning will feel as if they are in the teens to single digits, with wind chills closer to 30 degrees near the coast.
When the cold air slides atop Lakes Ontario and Erie from the west, it will spark rounds of lake-effect snow over adjacent Pennsylvania and New York state. Up to a foot of snow is possible through Wednesday east of Lake Ontario over the Tug Hill Plateau region.
About 5,000 feet above sea level, largely uninhibited by friction, air often flows quickly around storms in “low-level jets.” These atmospheric streams of fast-moving wind can lead to damaging surface gusts under certain conditions.
Because of the intensity of this Great Lakes storm, the associated low-level jet features unusually strong wind speeds. The atmosphere has a tendency to form a “cap” of relatively warm air a few thousand feet above the ground, which often inhibits the brisk winds of a low-level jet from fully mixing down to the surface. But some gusts can, especially if the cap is high enough or if the low-level jet is unusually strong.
Through Monday night, many parts of the Upper Midwest and interior Northeast could see gusts of at least 40 to 50 mph, especially areas just downwind of the Great Lakes. Early Monday, wind gusts reached around 60 mph near Duluth, Minn.
The National Weather Service in Buffalo issued a high-wind warning, calling for “damaging winds [that] will blow down trees and power lines,” with “widespread power outages … expected.”
Wind advisories cover eastern Wisconsin, northern Illinois, eastern Michigan, northern Ohio, Vermont and all but southern New York state.
As wind howls across the eastern Great Lakes, it will pile water against the shores in a surge event that could lead to minor coastal inundation. Lakeshore flood advisories and warnings have been issued for some counties that border the lakes, including for Buffalo.