Winter weather advisories and freeze warnings blanket much of central United States, with winter storm warnings in the Rockies where more than a foot of snow is possible. Snow was already falling moderately at times across Nebraska and Iowa on Monday morning.
The unusual meteorological setup features a low-pressure system over the Upper Peninsula of Michigan drifting east toward southern Ontario and Lake Superior, from which a strong cold front trails westward all the way to Montana. The west-to-east front was sagging southward as moisture pooled along it, sparking intermittent snow showers from the Intermountain West to the Corn Belt. Precipitation will increase in areal coverage and intensity as an upper-level disturbance moves over the surface front by Wednesday evening.
Snow initially focuses in the Rockies on Monday into early Tuesday
Most of the snow will be focused across southern Wyoming and Colorado late Monday into Tuesday, where winter storm warnings are up for the high elevations. Up to 14 inches of snow could fall from the quick-hitting system in Rocky Mountain National Park, the Medicine Bow Range and the Northern Front Range Foothills; most of the snow will come down in just a 12-hour window.
In Denver proper, three to six inches is expected, after six inches just fell Thursday night into Friday, with heavier amounts possible near the base of the foothills. Conditions will deteriorate by Monday afternoon in the Mile High City, where a winter weather advisory is in effect.
“Areas near the northern state border will likely see this begin around noon to 2pm, with snow surging into the Denver area in the 3pm to 5pm time frame,” wrote the National Weather Service in Boulder.
There was concern that the snow could fall moderate to heavy at times, impacting the evening commute. Rapidly cooling surface temperatures and the development of mid-level frontogenesis, or a change in temperature with horizontal distance a mile or so into the atmosphere, will favor enhanced lift, or upward motion, that should bolster snowfall rates.
Snow spreads east Tuesday and Wednesday, reaching the Midwest, Ohio Valley
That same band of snow will work into the Sand Hills of Nebraska before overspreading the Nebraska-Kansas border Monday night, arriving in the Kansas City area during the predawn hours Tuesday. Winter weather advisories blanket southern and central Kansas, where one to three inches is possible before the snow wraps up after lunch Tuesday. Kansas City proper and St. Joseph, Mo., could see an inch or two of slushy accumulation, primarily on grassy surfaces where ground temperatures remain sufficiently cool.
The band of snow could swipe through Chicago, too, primarily east of the city, before passing through the Ohio Valley. Indianapolis, Cleveland, Toledo and Buffalo could see rain changing to snow and accumulating a coating to two inches late Tuesday into midday Wednesday.
Meanwhile, temperatures will plummet behind the front, falling up to 30 degrees below typical springtime values in spots. Southwest Kansas could see highs in the lower 70s on Monday with temperatures falling below freezing by midnight.
In the Texas Panhandle, the front could act like what is known as a “blue norther,” a line of clouds heralding an abrupt temperature crash.
The cold air should make it all the way to the Gulf of Mexico by Wednesday, with most of the central United States waking up in the 30s to near 40. A few 20s are likely in the Dakotas and across the Northern Tier.
In Dallas, a century-old record could be broken. The lowest daily temperature observed April 21 was 39 degrees in 1918; the Weather Service is forecasting the morning to dip down to 37.
Oklahoma City could set a record, too, if it makes it down to 32 degrees. That’s the current forecast; a freeze warning is in effect.
New Orleans could even have a chilly night Wednesday night, with lows near 50. That’s not quite a record, but it is nippy for the Big Easy.
The cold air will reach the East Coast by Thursday morning, but will have moderated some, with temperatures about 10 to 15 degrees cooler than normal. Thursday night into Friday morning, parts of the interior Mid-Atlantic west of the Interstate 95 corridor can expect some late-season frost.
In the central United States, the entrenched cold air will begin to retreat Thursday and especially into Friday as warm, moist air overspreads the southern Plains ahead of an approaching low pressure system. That influx of warmth and humidity should set the stage for thunderstorms, a few of which could be strong to severe along the Interstate 35 corridor in Oklahoma and Texas.
A return to more seasonable to mild conditions in the eastern half of the Lower 48 is expected next week, along with an uptick in severe weather potential for the central United States.
Jason Samenow contributed to this report.