Arctic winds expected in Western Pennsylvania on Wednesday
The tatters of Super Typhoon Nuri battered the Bering Sea and its Aleutian Islands on Saturday with historic winds and rains, as the Lower 48 braced for the moment when the so-called bomb cyclone transmogrifies into something more like a polar bomb.
A mass of cold air from Western Canada will sweep down from the Northern Plains into the Great Lakes region, hitting Western Pennsylvania about Wednesday, said Brad Rehak, a meteorologist with the National Weather Service in Moon. Snow is not forecast.
“Starting Wednesday and continuing through the weekend, we expect high temperatures in the 30s and lows in the 20s,” Rehak said.
If misery loves company, the colossal size of the weather system might offer some comfort to those who are easily chilled.
“It’s going to encompass probably two-thirds of the United States, from the Rockies to the East Coast,” Rehak said.
A “bomb” as a meteorological term is a drop in a storm’s central pressure of more than 24 millibars in 24 hours. What remains of Nuri is expected to drop as much as 50 millibars in 24 hours— arguably a “double bomb.” It’s that intense low pressure that’s going to buckle the jet stream as ex-Nuri bulldozes across the Bering Sea.
Snow could start falling in Montana and the Great Lakes as Nuri forces a heavy wedge of Arctic air deep into the middle of the country.
“This strong low pressure system will cause the jet stream to buckle, creating a ridge in the western United States and solidifying a deep trough in the Eastern U.S.,” writes McCall Vrydaghs, a meteorologist for WHIO TV in Dayton, Ohio, predicting highs rising only into the low 30s for many parts of the country. “Keep in mind, if this same weather pattern were to set-up during the heart of winter, we would be looking at temperatures far lower.”
Indeed, the displaced Arctic air will mark another early attack of cold and snow on the East Coast that has been harangued by long, cold winters for several years.
Last Saturday, parts of the Appalachian South, including upstate South Carolina, saw significant early snowfalls of the kind that hadn’t been seen in 40 years.
The Farmer’s Almanac has called for an early and cold winter for large parts of the country, but research into another early and thick Siberian snowpack suggests that the winter may hang on, as well, deep into next year.
“There’s a theory that the amount of snow covering Eurasia in October is an indication of how much icy air will sweep down from the Arctic in December and January, pouring over parts of North America, Europe and East Asia,” writes Bloomberg’s Brian Sullivan. “Last year, the snow level across Eurasia was the fourth highest for the month in records going back to 1967. In January, frigid temperatures dubbed ‘the polar vortex’ slid out of the Arctic to freeze large portions of the U.S.”