WASHINGTON POST 4 NOVEMBER 2020 Unusual and enduring warmth to overspread central, eastern U.S.

By Matthew Cappucci, Washington Post, November 3, 2020

Abnormally mild weather is en route to the central and eastern United States to carry us into mid-November. High temperatures some 10 to 15 degrees above average are likely for about a week’s time, overspreading regions from the Plains and Mississippi Valley all the way to the Atlantic coast.

The predicted warmth is a dramatic turnaround from earlier this week, when a fall cold front swung through Sunday with howling winds, nippy temperatures and an insurgence of bone-dry air.

Now, highs could hit 70 in places like Washington, D.C., New York City, Chicago and perhaps even Boston, the balmy temperature set to stick around through at least Veterans Day (Nov. 11). In these locations, it will feel more like early October than early November.

High pressure in control

The warmth is all thanks to a slow-moving dome of high pressure, bringing southerly winds and sunshine to much of the southern and eastern United States. It was anchored over the South and Gulf Coast on Tuesday, but will saunter east, the core of it slipping offshore toward the Canadian Maritimes late week.

That ridge of high pressure will stall offshore, southerly winds on the western flank of its clockwise flow pumping warm, slightly more humid air up the Atlantic seaboard. All major weather systems will be diverted to the north and west, allowing about a week of tranquil, mild weather.That warm “blocking high” will probably begin to break down around Nov. 10 to 12.

Temperatures begin to increase on Wednesday, when winds shift more from the south and southeast for the eastern United States. D.C. should make it into the mid-60s, along with Chicago, Atlanta and Charlotte. The onshore flow will entrench New England in lingering cool air, with highs on Wednesday only in the lower 50s.

A temperature seesaw across the Lower 48

On Thursday, temperatures will really begin to spike, with highs some 25 degrees or more above normal in parts of the northern Plains and Intermountain West. Billings, Mont., and Casper, Wyo., could climb into the lower 70s. Both locations would ordinarily be in the upper 40s this time of year; Billings recorded 20 inches of snow in October. Denver will be in the 70s, too.

By Friday, 70 degrees is pretty much the magic number across most of the central and eastern United States. Highs in the lower 70s are likely from the Four Corners region east through the Plains. Minneapolis, a city that saw its earliest heavy snowfall on record this season after nearly 8 inches fell on Oct. 20, could nick the 70 degree mark. D.C., Baltimore, Philadelphia and New York could also flirt with or exceed 70 degrees, while Boston will likely enjoy mid- to upper 60s.

Meanwhile, a cold front will begin gathering over the West this weekend as a dip in the jet stream allows frigid air to descend south from Canada. Billings, which days before will have basked in springlike warmth, may not make it above freezing this weekend. In fact, the high on Sunday is predicted at 20 degrees. Casper, Bismarck, N.D., and Salt Lake City will all plummet into the upper 20s and lower to mid-30s by Sunday, with the cold reaching Denver and Minneapolis on Monday. Simultaneously, the nation’s temperature seesaw will continue to favor warmth in the East.

The prolonged above-average temperatures along the East Coast could last into the start of winter, albeit punctuated with intermittent spurts of chill. The National Weather Service Climate Prediction Center calls for increased odds of above-average temperatures over the East Coast, Ohio Valley and Southeast through at least mid-November, with slightly above-average conditions likely over much of the Lower 48 through February.

Matthew Cappucci Matthew Cappucci is a meteorologist for Capital Weather Gang. He earned a B.A. in atmospheric sciences from Harvard University in 2019, and has contributed to The Washington Post since he was 18. He is an avid storm chaser and adventurer, and covers all types of weather, climate science, and astronomy. URL: https://www.washingtonpost.com/weather/2020/11/03/eastern-us-warm-temperatur...