December 2018 to feature temperature swings, more large storms in eastern US
A winter storm barreled over Kansas, Missouri and other Midwestern states on November 25. This timelapse footage shows the snow piling up in the course of a day in Independence, Missouri.
The stormy weather pattern is forecast to continue, while temperatures are likely to flip back and forth from mild to cold in the eastern United States during much of December.
Expect several storms with the potential to disrupt travel and shipping from now through Christmas. While no long-term frigid conditions are forecast, prolonged abnormal warmth is also not likely in the East.
Three storms may roll through during a nine-day span
In the short term, one storm will move from the southern Rockies to the Upper Midwest into this weekend.
The storm this weekend has the potential to bring another blizzard to part of the Central states.
Except for a chance of spotty ice at the onset in the Appalachians and a wintry mix in the northern tier, the storm this weekend will bring mostly rain to the Northeast, with the potential for strong to severe thunderstorms in the South.
A second storm is forecast to reorganize over the Southwest states early next week then swing northeastward into midweek.
The track of that second storm will determine which areas receive rain and which areas in the Midwest and Northeast get some sort of snow or a wintry mix.
"There is the potential for a swath of snow or a rain and snow mix from the Ohio Valley to parts of the central and southern Appalachians, upper mid-Atlantic and southern New England areas, spanning Tuesday to Wednesday of next week," according to AccuWeather Senior Meteorologist Bernie Rayno.
Another storm may follow in a few days.
"The idea of a third storm is gaining momentum before the middle of the month," according to AccuWeather Lead Long-Range Meteorologist Paul Pastelok.
"That third storm spanning Dec. 7-9 could pack a punch in terms of heavy rain in the South and along the immediate Atlantic coast with the potential for heavy snow inland," Pastelok said.
With any of the storms, rain may lead to urban flooding and hinder travel on the highways, and fog and low clouds may lead to airline delays.
Where heavy snow falls, flight cancellations are more likely and travel on the roads may be very difficult.
The details will unfold in the coming days on the three storms.
"During the period from Dec. 10-20, the number of storms may decrease and/or the overall size of the storms may be such to affect a geographically smaller area," Pastelok said.
"The lull in storms is not likely to last through Christmas or even the days leading up to Christmas as the jet stream pattern looks to remain quite active due to El Niño," according to AccuWeather Long Range Meteorologist Max Vido.
"We expect the stormy pattern to resume during the latter part of December, but the exact track of a storm and which areas of the Central and Eastern states that might get heavy snow versus heavy rain cannot be determined this far out," Vido added.
Severe, long-lasting cold not foreseen
In terms of temperature, a break of mild weather is in store for much of the East beginning this weekend and lasting into early next week.
Download the free AccuWeather app to see when the best time is, relative to rainy episodes, to put up outdoor holiday lights or clean up the yard.
"It is possible that some areas along the Atlantic seaboard experience temperature departures of 10 degrees Fahrenheit or more above average for a couple of days during the period from Dec. 1-4," according to AccuWeather Lead Long-Range Meteorologist Paul Pastelok.
Average highs during early December range from the lower 40s F along the Maine coast to the lower 50s in Washington, D.C., to the middle 50s in Atlanta and the middle 60s in Charleston, South Carolina.
"For cold weather fans and skiing interests, temperatures are forecast to tumble around Wednesday, Dec. 5, and remain colder than average to approximately Tuesday, Dec. 11," Pastelok said.
During this approximate six-day period, there are likely to be areas of lake-effect snow, and there may even be some sort of weak Alberta clipper storm with light snow that races through from the Upper Midwest to the interior Northeast.
It is possible that another significant uptick in temperatures may coincide with any storm that rolls along during the second week of December.
"While we do not foresee long-lasting, extreme cold in the East during the two-week period from Dec. 12-25, we will have to monitor for any fluctuations in the Polar Vortex that lead to a southward discharge of cold air in North America or Europe," Pastelok said.
Even if temperatures end up within a few degrees of average during the third and fourth weeks of December, average temperatures trend down significantly from early December to the start of January.
Average temperatures are about 10 degrees lower during the end of the month, when compared to the beginning of the month.
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