Butler and Allegheny counties aren’t in the crosshairs of a predicted blockbuster storm expected to hit the Washington, D.C., region this weekend, but they could still get several inches of snowfall.

Lee Hendricks, a meteorologist at the National Weather Service’s Pittsburgh office, said Butler County is north of a weather advisory and storm warning that’s been put in effect from 1 p.m. Friday to 1 a.m. Sunday.

Northern Allegheny County is within a weather advisory area and is predicted to see between 3 and 6 inches of snow, with the heaviest portion falling between Friday evening and Saturday morning.

Hendricks said that it’s difficult to predict snowfall amounts when storms like the one expected to hit this weekend pass nearby but don’t hit the region directly.

“Because we’re on the back edge of this storm, the snowfall amounts will drop off rapidly,” he said. “We’re trying to guesstimate it right now, but it’s almost impossible to predict.”

To put out weather watches and advisories, the service has to have at least a 50 percent level of confidence in predictions, Hendricks said. That requirement jumps to 70 percent if a storm warning is issued.

Along with the snow, higher weekend temperatures are predicted.

Daytime temperatures from Friday through Sunday were expected to peak in the high 20s, with overnight lows ranging from 10 degrees Saturday to 19 Sunday.

The service says a total of 9 inches of snow has fallen on the region so far this January.

A national weather story is on Page 17.