A winter weather advisory is in effect until 10 a.m. today.

Kyle Pallozzi, a meteorologist for the National Weather Service in Sterling, said the advisory had been canceled Monday but was reinstated at 7 p.m.

Temperatures were to drop just below freezing Monday night, Pallozzi said, with a chance of freezing rain or sleet as well. Temperatures today will stay above freezing, he said, and the “vast majority of precipitation” will be “plain rain.”

Schools in Frederick, Shenandoah and Warren counties were closed on Monday after road conditions deteriorated overnight.

As of Monday afternoon, Shenandoah County Public Schools Superintendent Mark Johnston said he wasn’t sure whether schools would be closed again today.

“If temperatures don’t drop, we don’t get freezing conditions, I anticipate we’ll be open on time,” Johnston said. “I’ll have to withhold judgment. We usually decide at 3:30 a.m. and send messages out at 5.”

Inclement weather days have come hard and fast this year, but Johnston said he doesn’t imagine a circumstance where the school calendar will be affected. Johnston said the county has enough inclement weather days built so that there is still some wiggle room for school closures before the year gets extended.

“As of right now, counting today, we have missed about 10 days,” Johnston said on Monday. “We revert to 990 [instruction] hours when we can’t meet the 180-day requirement.”

Johnston broke down the “missed” days as eight full days of canceled instruction and two days once late starts and early dismissals are counted up.

The county’s public schools have slightly longer instruction hours than neighboring systems. A regular day for elementary students is equivalent to six instruction hours, and secondary schools’ regular days are 6 1 /2 hours, Johnston said.

Similarly, Warren County Public Schools Superintendent Greg Drescher said a call on school openings would have to wait until this morning.

Drescher wrote in an email that schools are using up scheduled weather days, and Monday’s closure represented the last of the “spring break” makeup days.

Steve Edwards, the coordinator of policy and communications for Frederick County Public Schools, said Monday afternoon it wasn’t clear what the decision for schools would be today.

Like Johnston, Edwards said Frederick County schools are not at risk of bumping up against an extended calendar.

“At this point,” Edwards said, “we look like we still have enough instructional hours to meet the 990-hour requirement.”

Contact Max Thornberry at mthornberry@nvdaily.com