The spate of warmth that prolonged September-like temperatures across much of the central, southern and eastern U.S. has come to an end. A jarring blast of cold has arrived, with abnormally chilly weather for mid-November and even an early-season snowstorm on the way for some areas.
Winter storm warnings are in effect just west of Oklahoma City, where up to 6 inches of snow could fall Monday, with more expansive winter weather advisories stretching from the Texas Panhandle to northern Missouri as well as parts of Minnesota. That same strip of snow could push through the Midwest and into New England through the middle of the week.
That storm heralds a reinforcing shot of bone-chilling air descending south out of Canada, with temperatures expected to dip some 20 to 30 degrees below average. By this upcoming weekend, readings across the northern Plains and Upper Midwest may struggle to climb out of the middle teens during the day, and could fall below zero at night.
Over the coming week, 100 million Americans are slated to experience temperatures below 20 degrees.
The chilly air isn’t coming as a single surge of Arctic cold, but rather as a series of Canadian coughs and sputters. A string of cold fronts, each bringing colder air than its predecessor, will roll across the central and eastern U.S.
The first rolled through over the weekend, bringing an end to the “second summer” that had been maintaining balmy weather in the eastern half of the nation. Washington D.C., for instance, had made it above 70 degrees a record 10 times in the first 12 days of the month. Saturday’s high was 72 degrees, but Sunday’s high temperature of 54 matched Saturday’s low.
New York City, where the average mid-November high is in the mid-50s, came within a degree of records last Tuesday when Central Park made it to 77 degrees. Now they’re looking at highs in the 40s every day this week, with a chance that Saturday doesn’t climb out of the 30s.
And in Boston, where highs this time of year are typically in the lower 50s, the month to date has been running 11 degrees above normal, both Nov. 6 and last Saturday hit a record of 76. Heading forward, highs this week should tend toward the 40s to near 50, with lows in the upper 20s to lower 30s.
In the Midwest and around the Great Lakes, Mother Nature’s caprice has been even more dramatic. Chicago peaked at 76 degrees last Thursday. Saturday was an astonishing 40 degrees colder with a high of only 36.
From Chicago, Milwaukee, St. Louis and Little Rock eastward, the first 12 days of November averaged 8 to 15 degrees above normal.
Unfortunately for summer lovers, the cold isn’t going anywhere anytime soon. The National Weather Service’s Climate Prediction Center is calling for odds of below-average temperatures for most of the country, save for Alaska, Florida and the Pacific Northwest.
The second of the cold frontal trio is marching across the Plains to kick off the workweek, trailing south of a fledgling low-pressure system in the James River Valley of South Dakota. A second low is beginning to strengthen in Kansas on that front, energized by an approaching strong shortwave — or pocket of cold air, low pressure and spin — kicking east out of the Four Corners.
That’s generating a full-fledged snowstorm over Oklahoma, with rain in southeastern parts of the Sooner State and snow behind the front to the northwest.
Doug Speheger, a meteorologist at the National Weather Service in Norman, Okla., said the storm arriving in the area Monday is expected to produce the heaviest snow in a narrow band. “Our temperature profile is kind of right on the edge of rain versus snow … around or just above 32,” he said. “We’ll see the atmosphere dynamically cooling right near the center of the upper-level storm system. We’ll see a narrow axis of snow.”
The agency is predicting half an inch or less in Oklahoma City, but up to half a foot could fall about 100 miles west of the state capital.
Speheger says it’s “fairly unusual” to see a significant snowfall so early in the season, but that it’s “not unheard of.”
In Clinton, Okla., what falls Monday could total to the earliest four-inch snow event on record for the winter season. It could outpace the plowable snowfall that occurred on Nov. 20, 1988. Chickasha will likely nab a similar record.
“We’ve had it all going on this November,” Speheger said. “We did have the tornadoes that affected southeast Oklahoma, including a couple EF4s that moved in from Northeast Texas, on November 4. Then last Friday, we had a little bit of snow move through in central Oklahoma, so we definitely kind of pulled the trigger from spring.”
Winter storm warnings are in effect for Oklahoma City, with advisories for snowfall in Wichita and Topeka, Kan., and Columbia, Mo. Even the Kansas City area could see 1 to 3 inches of snow on Monday night, and it is under a winter weather advisory.
“Plan on slippery road conditions,” wrote the National Weather Service in Pleasant Hill, Mo. “The hazardous conditions could impact the [Tuesday] morning commute.”
Farther north, a winter weather advisory is also in effect for Minneapolis into Monday night where 2 to 4 inches of snow is expected.
That same disturbance could bring snow to the Midwest on Tuesday, including in Chicago and Indianapolis, which could each see about an inch.
Then the system is forecast to deliver a few inches to western and central New England late Tuesday into Wednesday. The coldest air of the season will follow. As that cold air blows over the Great Lakes, significant lake-effect snow could develop downwind of lakes Superior, Michigan, Ontario and Erie on Thursday into the weekend.