A trifecta of winter weather that came about a dozen days before the official start of the season will be capped with a rush-hour snowstorm Tuesday morning, completing a 48-hour cycle of misery that delivered snow, sleet and freezing rain.

Weather forecasters and the officials who heed them warned that the morning rush hour could be as dicey as it was Monday, when the federal government started work two hours late and many school districts shut down.

Fairfax County schools said they would close again Tuesday, for the second successive day. Prince William County schools also cheered up their students with the news that the day was theirs to enjoy.

Temperatures that rose Monday — turning sleet into steady rain by midday — were expected to fall Tuesday morning. Intense snow was forecast during rush hour, with 3 to 5 inches piling up before the storm moves on later in the day.

“The upcoming storm will present some challenges,” said William O. Howland Jr., director of the District’s Department of Public Works. “Sleet is expected to start falling during the early morning rush hour before changing to snow about 8 a.m. That means traffic can be affected, so we urge motorists to travel cautiously.”

The warning that the storm front had a second punch came as many area transportation agencies gave their road crews a rest. Some had worked through the night Sunday and into Monday to deal with icy highways and side streets.

“As far as crews, we will get them home to rest, assuming the forecast remains,” said Valerie Burnette Edgar of Maryland’s State Highway Administration. “Generally we keep some folks or contractors in [service].”

In Virginia, the crews that clear and salt the roadways work 12-hour shifts in rotation during prolonged winter storms.

“They would tell you they are not tired, but energized by the weather — many of them love this stuff,” said Joan Morris of Virginia’s Department of Transportation.

The bad weather didn’t stop President Obama, first lady Michelle Obama, former secretary of state Hillary Rodham Clinton, former president George W. Bush and his wife, Laura Bush, from boarding Air Force One on Monday at a foggy Joint Base Andrews for a flight to South Africa to attend memorial events for Nelson Mandela.

By Monday morning, several inches of snow had accumulated in the western and northern parts of the region. Closer to the District, the wintry mix that started Sunday changed from snow to freezing rain and eventually rain.

Commuters found slick roads in some areas as temperatures hovered just above freezing during the Monday morning commute, and police and highway officials reminded drivers to slow down.

An overturned tractor-trailer full of tires caused some lanes on the outer loop of the Capital Beltway at Chain Bridge Road near Tysons Corner to close temporarily early Monday. Just after 8 a.m., the Beltway’s southbound lanes had reopened, officials said.

On Metro, rail lines operated with no delays, and Metrobus routes also ran as planned Monday morning. Delays on some VRE lines coming from Fredericksburg were caused by downed trees.

In some neighborhoods, trees weighed down by ice fell onto power lines and streets. Power companies reported storm-related outages, which increased throughout the morning as crews worked to repair lines.

By 9 p.m. Monday, power had been restored to all but about 100 customers in the District and its Maryland suburbs. About 15,000 customers were without electricity in Northern Virginia, two-thirds of them in Fairfax County.

The U.S. Senate postponed a series of votes scheduled for Monday evening because of inclement weather.

Sen. Majority Leader Harry M. Reid (D-Nev.) announced Monday afternoon that votes scheduled for the evening would be postponed until Tuesday morning. Reid said Senate leaders had been scrambling most of the day to determine whether enough senators would return in time for the votes.

The delay also means that a vote to confirm Patricia A. Millett to serve on the U.S. Court of Appeals for the District of Columbia Circuit will have to wait until at least Tuesday. Millett is expected to be the first of three presidential nominees to serve on the powerful court. Senate Democrats would like to confirm the nomination by the end of the year.

In addition to weather-related absences, at least two senators were not scheduled to be in Washington on Monday: Sen. Ted Cruz (R-Tex.) is part of the congressional delegation traveling to South Africa to attend a memorial service for Mandela, and Sen. Mark Kirk (R-Ill.) is recovering from gall bladder surgery.

While notable, the postponement is nothing new: This is at least the third time this year that the Senate has postponed Monday evening votes because of bad weather or the lack of a quorum.

Mark Berman, Martin Weil and Ed O’Keefe contributed to this report.

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