Washington’s first snowfall of 2014 fell short of a blizzard, but Friday morning’s commute could be slow, slick and dangerous as the storm’s second punch was expected to bring some of the region’s coldest weather this season.

“Roads that are slushy or wet from snow overnight will rapidly freeze towards morning due to plummeting temperatures,” said Capital Weather Gang forecaster Jason Samenow. “By dawn, temperatures will range from around 15-20 degrees with a punishing wind chill.”

The U.S. Office of Personnel Management announced shortly before 10 p.m. that federal agencies in the region would be open but that workers had the option for unscheduled leave or telework.

By 8:30 p.m., 4.25 inches of snow had fallen in Leesburg, and 3.5 inches in Columbia. Vienna had about a half-inch.

Carl Barnes, a National Weather Service meteorologist, said temperatures would climb only into the low 20s Friday. Windy conditions would make it feel near zero, with even lower readings possible in the western suburbs.

“We have potential for very hazardous conditions,” Barnes said. “These are pretty extreme wind-chill factors.”

Amtrak announced modified service Friday along the eastern corridor. Acela and Northeast Regional trains were scheduled to run between the District and Boston but at reduced frequency.

Power companies reported few outages late Thursday, with Pepco reporting about 1,500, mostly in the Rockville and North Bethesda areas. But high winds were expected Friday, making more outages possible.

At the region’s three major airports, officials reported flight delays and cancellations late Thursday and braced for more such misfortune on Friday because of blizzard conditions forecast for the Northeast. Airport officials urged passengers to check with their airlines about delays and cancellations.

Thursday’s snow didn’t paralyze the evening commute, but it did cause dozens of minor mishaps in Loudoun, Fairfax and Montgomery counties. No serious injuries were reported.

As of Thursday evening, public schools in Loudoun, Stafford and Clarke counties, all in Virginia, were closed for Friday.