Weather for Inauguration Day to hinge on early-week East Coast storm

Joe Biden will be sworn in as the 46th President of the United States on the West Lawn of the U.S. Capitol on Wednesday, Jan. 20, 2021, in an outdoor tradition that has faced inclement weather hurdles in the past and may be no exception this year. Vice-President-Elect Kamala Harris will take the Oath of Office alongside the president-elect followed by an inaugural address.

The overall weather pattern is expected to trend toward much colder conditions during the third and fourth weeks of January compared to conditions experienced in the Central and Eastern states so far during the first month of the year. Temperatures in the nation's capital this week could climb into the mid-50s, more than 10 degrees above average.

As the weather turns colder and even after Arctic air settles in, stormy weather conditions may result. However, exactly how stormy it becomes is not yet clear, according to forecasters.

"We have been and continue to focus on the potential for a significant storm in the eastern part of the U.S. early next week," according to AccuWeather Lead Long-Range Meteorologist Paul Pastelok.

AccuWeather's long-range team has been monitoring changes in air temperature in high levels of the atmosphere since late December, which suggested that the polar vortex would weaken and allow much colder air to plunge southward into North America around the middle of January.

A large chunk of colder air is set to move southward later this week and replace above-average warmth with snow and more seasonable temperatures in the Midwest. Areas of snow and localized snow squalls and lake-effect snowfall will develop as the colder air arrives.

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A much more substantial outbreak of Arctic air is predicted across the North Central states later in the month, and AccuWeather forecasters say some of that cold air will spill farther to the south and east as well, bringing along the potential for unsettled weather.

"The forecast jet stream pattern is pointing toward a big storm that would travel from the southern Plains to the Atlantic coast early next week," Pastelok said.

"We expect a storm to bring a wintry mix from the southern Plains on Sunday, Jan. 17, to the Tennessee and Ohio valleys on Monday, Jan. 18," Pastelok explained.

Cold air should be in place across the mid-Atlantic and Northeast states as the storm moves through on Tuesday, Jan. 19.

"Should the storm develop to its full potential, blizzard conditions can't be ruled out," Pastelok stated. Impacts from this potential storm could include power outages and disruptions to virtual schooling and businesses, he added. Travel during and shortly after the storm on Inauguration Day could be adversely affected in this scenario.

Another scenario wouldn't involve a large storm, but rather more of a progressively colder weather pattern with some weaker and quick-moving storms that originate from western Canada and press southeastward across the Northeast states.

Each one of these storms would be accompanied by rising temperatures as the systems approach, only to be followed by falling temperatures in their wake. Snow showers or batches of brief snow and mixed precipitation could occur as these weather systems move along.

This sort of pattern may not only set up in the absence of a big storm but also in the wake of a major storm during the middle and latter part of next week.

A large storm would likely usher in colder air, drawing it southeastward from the Midwest, although the air would warm up some as gusty winds blow downhill from the Appalachians. If a major storm drops accumulating snow on the Washington, D.C., area on Jan. 19, snow cover could also influence and lower temperatures further.

High temperatures in Washington, D.C., on Inauguration Day could be in the lower 30s with blustery and cold conditions despite clouds giving way to sunshine. AccuWeather RealFeel® Temperatures could be in the 20s in this case.

On the other hand, if no major coastal storm takes shape and a series of weaker storms approaches instead, the timing of temperature swings can have a significant impact on temperatures in the Washington, D.C., area and much of the Atlantic coast next week.

If there is no big storm and a weaker clipper storm is traveling across the Great Lakes toward the central Appalachians, then temperatures could spike well into the 40s on Inauguration Day. If that clipper storm were to move along at a swifter pace, then temperatures may struggle to climb out of the 30s and could dip further during the day.

Either way, the coldest air would tend to focus over the North Central states, before that air is warmed a bit by the open waters of the Great Lakes and the downhill flow from the Appalachians.

At this time, AccuWeather meteorologists are forecasting mainly dry conditions with temperatures a bit below average, in the upper 30s, for Washington, D.C., on Inauguration Day. Conditions should allow for at least partial sunshine.

The normal high for the nation's capitol is in the lower 40s. A stiff breeze would result in lower AccuWeather RealFeel® Temperatures in the upper 20s.

Highs in the upper 30s would be substantially colder than most days so far this month in the nation's capitol. Temperatures have averaged nearly 5 degrees above normal during the first 10 days of the month with temperatures as high as 58 on Jan. 2 at Reagan National Airport. The lowest high temperature since Dec. 1, 2020, has been 37 on multiple dates. Much of the nation will continue to experience above-average temperatures for several more days this week.

AccuWeather meteorologists will continue to closely monitor the weather for Inauguration Day in Washington, D.C., as well as all weather patterns throughout the nation in the coming days.

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