How weather affected the last attack on the Capitol

The last time the U.S. Capitol was attacked and damaged was in 1814. On Aug. 25, British soldiers set fire to the buildings in the Capitol area. As in the first battle, the attack on Jan. 6, 2021, seemed to catch the defenders off-guard. The late David Ludlum's 1970 book, "Early American Tornadoes 1586 to 1870", tells the story, "The city of Washington underwent a double ordeal 25 August 1814 when man and nature combined to deal the Nation's Capital the greatest disasters in it has ever experienced. While the public buildings were in flames from the British torch, a tornado smashed through the area doing major structural damage in the residential section. More British soldiers were killed and wounded by this stroke of nature than from all the firearms the American troops had mustered in the ineffective defense of the city.
Following the Battle of Bladensburg on 24 August to the northeast of the city, the British troops moved into the capital without organized opposition. Next morning, the 25th, they set fire to the Capitol, the White House, most public office buildings, and several residences. This was in retaliation for the American burning during a previous summer of the public buildings at York (now Toronto), the capital of Upper Canada (now Ontario). 
While the conflagration raged along Pennsylvania Avenue, the skies darkened to the westward and soon the city was enveloped by a severe storm of wind and rain. That this was a true tornado and not a local whirlwind caused by the convection of rising heat from the fires was attested by the presence of tornadoes to the northwestward of the city on the same day."

Two snowstorms will move across parts of the south within the next five days, and it does not appear that any major snowfall will affect the Northeast for a much longer time. The GFS forecast of snowfall between now and almost Jan. 23, shows this idea:

There are signs of one or more Arctic blast(s) moving into the Northeast starting late next week. This is a GFS forecast for next Friday night: