‘Dicey forecast’: How much snow? How much rain?

Get ready for some wild, winter weather across the broader D.C. region Wednesday with a heavy blast of snow to the north and west and a deluge of rain to the south bringing potential flooding threats.

Here’s what you need to know.

The National Weather Service has issued a winter weather advisory for lower Montgomery, Fairfax, Prince William, southern Fauquier, eastern Howard counties as well as Baltimore City.

The weather service said mixed precipitation is expected with total snow and sleet accumulations of 1 to 3 with snow spreading over the area in the morning hours before changing to sleet and freezing rain in the afternoon.

Points to the south, including D.C., itself, are likely to see the snow quickly turn to rain, and Southern Maryland will likely just see rain all day.

If you’re a snow-lover in the heart of D.C., this will likely not be an early Christmas present: Storm Team4 meteorologist Amelia Draper said she’s not expecting much “if anything at all in the way of accumulation right around the Beltway.” However, some parts of the region may become “a winter wonderland.”

That’s because points north and west of D.C. — upper Montgomery, Loudoun, northern Fauquier, Frederick counties in both Maryland and Virginia, and the panhandle of West Virginia — are under a winter storm warning, with heavier snow expected, as much as 12 to 18 inches, making travel very difficult or impossible, the weather service said.

Here’s a map of the areas under the winter storm warning and winter storm watches as well as snow totals forecast by the weather service.

Here is our most likely snowfall accumulation map. As you can see, there is a tight gradient of snowfall accumulations along the urban corridor of Baltimore/Washington. Areas east of here will see mainly a cold rain, whereas 30 miles to the west could see over 12″ of snow. pic.twitter.com/DbFKrnBQI1

— NWS Baltimore-Washington (@NWS_BaltWash) December 14, 2020

Storm Team4 meteorologist Chuck Bell said the rain-snow line is making for a “dicey forecast” in some parts of the region.

The precipitation is set to arrive after the sun comes up Wednesday. For most of the area, it could start as snow. “Areas northwest of Washington — Frederick County, Maryland out to Frederick County, Virginia; Martinsburg, West Virginia — they’re likely to start and stay snow through most, if not all, of the upcoming event,” Bell said. “That means snow amounts will be highest in those areas.”

But closer to the D.C. area, the rain-snow line comes into play.

“The closer you get to Washington, the lower the snow totals are going to be,” he said.

From Montgomery to Fairfax County, Arlington, D.C. and Prince George’s counties, “all are likely to start as snow, and then have some slushy accumulation before a big input of warm air changes most of that over to … cold rain and about 35 degrees tomorrow afternoon and evening,” Bell said.

There’s a chance the rain could switch back over to snow again, but it’s looking like the northern and western D.C. suburbs in Maryland Virginia will see “probably a slushy 2 to 4 inches before the rain switches in and then maybe another light little coating of snow at the end,” he said.

East of D.C. into Annapolis and Southern Maryland snowflakes will be hard to come by, but the rain could prompt flood concerns. There’s a flood watch for Anne Arundel, Prince George’s, Charles and Calvert counties in Maryland. Heavy rainfall is expected to bring 1 to 2 inches of rain with isolated flooding, the weather service said.

Want a different amount? Ask a different computer. This first image is our @nbcwashington forecast. The other 3 are various forecast models. Good agreement in general even with different specifics. My full write up is on Facebook, just search Chuck Bell 4, look for blue check. pic.twitter.com/jGRj4Bh9T7

— Chuck Bell (@ChuckBell4) December 15, 2020

Roads

The predictions have local authorities working to get residents prepared for a significant winter weather event.

Maryland Gov. Larry Hogan activated governmentwide response effort to prepare for heavy snowfall.

“As our state braces for its first major winter weather event this season, we have mobilized an all-hands-on-deck effort to keep Marylanders safe,” Hogan said in a statement. “Stay tuned to your local forecasts for the latest updates, heed the guidance of state and local authorities, and most importantly, use common sense.”

When it comes to keeping the road clear, Maryland State Highway Administration’s Shanteé Felix said the state has up to 2,700 pieces of equipment ready to be deployed.

She said that the highway department is advising the public that if you don’t have to be out on Wednesday and Thursday, stay at home. If you do need to be out, watch your speed.

“Those posted speed limits that you see, those are for ideal weather conditions so in the snow you want to drive 5 to 10 mph slower than you ordinarily would and if you find yourself out on the road with our equipment, please drive slower and give our crews plenty of space to clear the road,” Felix said.

Felix said pre-treating the roads is tricky.

“We’re going to pre-treat where we can. Usually when it rains we can’t pre-treat since rain washes it out, so where we can that’s how we’re going to address it,” Felix said.

Officials in Prince George’s County said the Department of Public Works and Transportation was mobilizing for the expected bad weather. If snow plowing is needed, primary and secondary routes will be serviced first, followed by residential routes.

The Montgomery County Department of Transportation said its crews are also preparing for the winter storm. The county said its snow operations center will be activated virtually and that crews in depots will be limited and practicing social distancing.

“Due to these circumstances, normal service times may be impacted,” the department said in a news release. “Crews will respond as quickly and as safety as possible.”

Crews will begin plowing roadways once at least 3 inches of snow have fallen, the county said.

School status

Because of the coronavirus pandemic, most students across the region are already at home attending schools through online classes. So what happens to snow days? It depends.

In Loudoun County, Virginia, distance learning and any on-campus activities are canceled for Wednesday. District offices will also be closed, and there will also be no food pick-up or deliveries.

Earlier, the district announced that “snow days” would still be observed this winter.

“As in years past, LCPS central staff will continue to monitor forecasts and existing conditions and make determinations for inclement weather closures and delays on a case-by-case basis,” Kevin Lewis, assistant superintendent of Loudoun County Public Schools Support Services said in the statement.

LCPS said this decision was made because, “while it may seem that continuing with the school day through remote instruction is feasible, many other factors also have to be considered.”

Fairfax County said school buildings would be closed but students would continue with teacher-led virtual learning. You can see the list of canceled school activities on the Fairfax County Public Schools website.

Fauquier County Public Schools in Virginia — where the area is expected to see several inches of snow — announced Tuesday afternoon it was canceling virtual classes Wednesday and Thursday.

All FCPS classes will be canceled on Wednesday, December 16, and Thursday, December 17. Teachers may post and communicate the location of optional learning resources for students. All school buildings and offices will be closed on Wednesday, December 16.#fcps1kidsdeserveit

— Fauquier Schools VA – NEWS (@FCPS1News) December 15, 2020

They said these factors include public utilities affected by the weather and road conditions for those teachers instructing remotely from their classrooms.

A spokesperson for Prince George’s County Public Schools, which remains in all-virtual learning for students, told WTOP that children will be required to join classes in the Maryland county even during snow or inclement weather.

In the event that the weather knocks out internet access, the school system said, “Students can report their tech outage to their teacher as stated in the current distance learning guidelines.”

Teachers currently have the option to conduct either online or in-person instruction, but during a snowstorm, PGCPS said teachers “would be asked to work from home.”

In Frederick County, Maryland, students will continue to learn through virtual instruction using the current schedule if there are any upcoming snow days, according to a school system statement.

An announcement canceling small group instruction will be made by 5 a.m. on inclement weather days, and those students will participate in virtual learning for the day.

If the weather event is significant enough to close school offices in Frederick County, then an announcement will be made that the entire system is closed and no virtual instruction will happen, according to FCPS.

This will be considered a “snow day” and the day will be made up as outlined by the school system.

While in virtual, small groups or hybrid instructional models in Howard County, the school system is transitioning to fully virtual instruction during inclement weather days.

“This will allow the school system to make a decision earlier when inclement weather is expected and provide families with earlier notice so they may make necessary adjustments,” the school system said in an announcement.

WTOP also contacted schools systems in Montgomery and Fairfax Counties and is waiting for comment.