A burst of painful cold is following a storm that unleashed rain along the Eastern Seaboard and more snow in the northern tier as a weather pattern seemingly stuck on repeat this winter plays out yet again.
Even though Arctic air of the magnitude forecast for the eastern United States is quite common during the middle of February, the frigid conditions to continue to sweep in through Friday night could be a shock for millions, to say the least, amid what has largely been a mild winter season. Meanwhile, the northern Plains and Upper Midwest will face downright dangerous conditions with this bitter blast into the start of the weekend.
It has been a warm winter for much of the East with temperature departures ranging from 4 to 8 degrees Fahrenheit above average.
Temperatures are expected to take a nosedive and drop off by as much as 30 to 50 degrees Fahrenheit by Friday night.
Friday's highs could even be 15-25 degrees lower than Thursday's. Temperatures were struggling to rise past the single digits from northern New England to western and central New York state during Friday afternoon.
Temperatures that ranged from the 30s across northern New England to the 80s in the South on Thursday will be swapped with Saturday morning temperatures below zero in the northern tier to the 20s and 30s in much of the South.
By Saturday morning, many thermometers in the region will be registering their lowest marks of the winter or may come within a couple of degrees of the season's benchmark set way back in mid-December during an earlier outbreak of Arctic air.
In New York City, the temperature has dipped into the teens only once this winter season. That episode was during the brief cold snap ahead of Christmas on Dec. 19, prior to the official start of winter, Dec. 21. The period from Dec. 1 to March 1 is typically the coldest three months of the year in the Big Apple and much of the East.
The upcoming Arctic outbreak will be brief but result in a surge of heating demands and have people hunting for their hats and gloves that may have been tossed aside in recent weeks.
The penetrating cold could result in some damage to buds that have softened up due to mild winter conditions, particularly on some fruit trees and non-native grapevines from Michigan to upstate New York and Pennsylvania.
The warmup that commenced over the northern Plains on Friday will progress eastward. Temperatures are forecast to rebound over the second part of the weekend in the Northeast. In some cases, low temperatures from Saturday morning to Sunday morning may be 20 degrees higher.
People who mind the cold or who have health risks for venturing out in cold weather may be able to get back out by Sunday.
However, additional bursts of Arctic air can follow through the rest of February.
"Back-and-forth mild and cold weather conditions are likely to continue for the remainder of the month," AccuWeather Lead Long-Range Meteorologist Paul Pastelok said.
"We are actually lowering our long-range forecast temperatures for around Feb. 20 and 21," Pastelok said.
It is possible there is another plunge in temperature in the next couple of weeks that is within a few degrees of the one into Saturday.
"We are trending temperatures down in areas of the Midwest from double-digit above-average to lower single-digit above average and even trending parts of the Northeast to below average for part of the latter half of the month," he said, adding that computer models have had a tough time picking up on storm timing, track and the magnitude of cold this winter season.
Normal temperatures trend upward from the beginning to end of February by an average of 5-10 degrees. This means that the same temperature may be well above average right now but may be below average by late-February.
Lengthening daylight and a slightly higher sun angle in February are the main contributors to the climbing temperature trend. Temperatures typically increase at an even faster pace during March and April.
Cold waves through the end of February will be brief as the polar vortex is forecast to generally remain strong and hover near its home position above the Arctic Circle.
Over the next week or so, conditions look to be void of substantial snow from the central Appalachians to the coastal Northeast. However, there is still a chance the occasional cold waves may hook up with a storm in just the right way for snow to occur prior to the end of the month and even farther ahead into March.
"The pattern will not be void of storms, so there is always a risk of a snow event on the East Coast, even during a mild winter and an average spring," Pastelok said.
A strong atmospheric roadblock over Greenland and the Atlantic Ocean is not needed for a snowfall or two over the central Appalachians and coastal Northeast -- but that pattern would be needed to set the region up for a major snowstorm. AccuWeather forecasters are not seeing indications that this type of blocking pattern will develop.
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