Just as people in the Midwest and East become accustomed to April and even May-like warmth, winter will return to send a shock to these regions before Easter weekend begins.
Temperatures since the start of spring on March 19 have averaged around 3 degrees above normal in Chicago and New York City and nearly 5 degrees above normal in Washington, D.C., adding to the potential shock factor.
Arctic air will blast into the northern Plains and western Great Lakes region on Wednesday as a strengthening storm from western Canada, known as an Alberta clipper, moves east across Ontario. Alberta clipper storms are typically quick-moving systems that are moisture-starved.
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The clipper storm has the potential to develop into a bomb cyclone as it travels from southwestern Quebec to coastal New Brunswick, Canada, from Thursday to Friday. A bomb cyclone is a storm that strengthens so rapidly that the central barometric pressure plummets 0.71 of an inch of mercury or more in 24 hours.
Even if the storm falls short of the official criteria, the effects of this rapidly strengthening storm will generate snow and gusty winds in addition to the cold air.
"The cold blast will surely bring the perception that winter has returned," AccuWeather meteorologist Courtney Travis said.Temperatures will be slashed in the wake of the cold front that is forecast to sweep across more than 2 million square miles of the United States from Wednesday to Friday.
The strengthening clipper storm and associated southward plunge in the jet stream will allow the colder air to spread all the way to the Gulf Coast and Atlantic Seaboard by the end of the week.
Areas from the Upper Midwest to the central Appalachians are likely to have the most extreme drop in temperature with highs in the 60s and 70s F at midweek being swapped with highs in the 40s and 50s by the end of the week.
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Even in the South, AccuWeather temperatures that feel like the 80s to near 90 Wednesday and Thursday will be exchanged with temperatures that feel like the 30s, 40s and 50s by Friday, and this will be quite a shock.
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For example, in Charlottesville, Va., temperatures will feel like up to the lower 80s on Wednesday afternoon, but they will be in the upper 20s to near 30 by Friday morning. A frost or freeze is possible both Friday and Saturday morning over the Shenandoah Valley and perhaps in other locations where blossoms have emerged early due to recent warmth. These blossoms could be damaged.
Farther to the north, the strengthening storm will produce a batch of moderate to heavy snow from northern New England to portions of southeastern Quebec and New Brunswick from Thursday afternoon to Friday.
"Some accumulating snow is likely to fall as far south as the southern tier of central and western New York state, northwestern Pennsylvania and western Massachusetts from the storm," Brian Wimer, AccuWeather winter weather expert, said.
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There is the potential for a foot of snow to fall in some areas.
"There can even be snow showers that extend as far south as western Maryland, northern West Virginia and northwestern Virginia for a time," Wimer added.
Gusty winds generated by the strengthening storm could be strong enough to break tree limbs, which, in turn, could lead to sporadic power outages and can threaten trouble for tents and canopies set up at outdoor triage and testing centers for COVID-19.
"Frequent gusts between 35 and 45 mph are anticipated from the Great Lakes to the central Appalachians and the New England and mid-Atlantic coasts," AccuWeather senior meteorologist Brett Anderson said. "Locally higher gusts are possible," up to 55 mph.
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Winds this strong can not only toss trash cans through neighborhoods, but also cause water to build up along the southern- and eastern-facing shorelines of the Great Lakes.
Since Great Lakes waters are at very high levels and are generally free of ice, lakeshore flooding is likely.
