Baltimore City experiences the first snowfall of 2016. (Karl Merton Ferron, Baltimore Sun video)
More than a foot and a half of snow is expected to fall over a day and a half starting Friday night in what forecasters predict could be one of the Baltimore region's biggest storms on record.
Winds gusting up to 40 or 50 mph could create blizzard conditions and large snow drifts. The National Weather Service placed the region under a blizzard watch from Friday afternoon through Sunday morning, something it has not done in this region since 1993.
The slow-moving storm is expected to be on par with the memorable — and crippling — snowfalls of February 2010, February 2003, January 1996 and February 1983.
"We're calling for a top-10 storm and possibly top-five storm," said Bryan Jackson, a meteorologist with the National Weather Service's Baltimore/Washington forecast office.
Meteorologists foresee a classic setup blamed for so many of those historic storms.
A system that was passing over the mountains of Wyoming and Idaho on Wednesday is expected to dip southward to Texas and Louisiana on Thursday, picking up Gulf of Mexico moisture before pivoting to the northeast and crawling up the Mid-Atlantic coast Saturday. It is forecast to strengthen as it meets cold air to its north and relatively mild, moist air over the Atlantic.
That clash of cold, dry air and the warmer, wetter flow off the ocean could produce snowfall at rates of 2 or 3 inches per hour and even some thunder and lightning late Friday night and during the day Saturday, said Brian Edwards, a meteorologist with AccuWeather.com. Significant coastal erosion and flooding also are expected.
The weather service's forecasts call for the heaviest snow, more than 2 feet, in the higher elevations of Virginia southwest of Washington, and 1 1/2 to 2 feet along the Interstate 95 corridor. Other forecasters, including AccuWeather and local television stations, made similar predictions.
Virginia Gov. Terry McAuliffe declared a state of emergency Thursday, with the storm set to arrive there by early Friday.
While forecasters were confident in their predictions of a major storm, they acknowledged some uncertainty over predictions of snow accumulations. If the storm tracks farther inland than expected, it could pull more relatively mild ocean air overhead, creating more mixed precipitation and cutting down on snow totals.
"That's the one big thing to keep an eye on," Edwards said.
Weather service forecasters said a fast-moving current of wind in the atmosphere expected to develop over the region Saturday could allow some milder air to move into the middle levels of the atmosphere, causing some sleet to mix in with snow and reducing snow totals. But that is more likely in Southern Maryland, they said, and it was unclear Thursday morning how far north the mixed precipitation might extend.
The forecast prompted the University of Maryland, College Park to announce it is closing Friday, Saturday and Sunday, disrupting move-in weekend for the spring semester. The university asked students not to move in Saturday. Spring semester classes are scheduled to begin Monday at that university as well as the University of Maryland, Baltimore County and Towson University.
The Maryland Emergency Management Agency urged residents to prepare by keeping devices charged and making plans to check on friends, neighbors and relatives. The strong winds and heavy, wet snow could cause power outages.
Officials urged people not to drive once snow starts falling, if possible, because of a high risk of vehicles being stranded. State and county crews are nonetheless readying their plows and salt trucks.
"State agencies are coordinating all available resources to prepare to clear roads and manage incidents that may be caused by this significant storm, but Marylanders should also take action now," Gov. Larry Hogan said in a statement.
The weekend storm follows a system that swept through the region Wednesday night, forecast to drop a dusting to an inch of snow south of Baltimore.
The heaviest snow fell between 9 and 10 p.m. in Baltimore, which saw about 0.5 inches, said Ray Martin, a meteorologist with the National Weather Service. Parts of Garrett County reported the most accumulation: 2.5 inches, he said. The total at Baltimore/Washington International Thurgood Marshall Airport was not available Wednesday night, but 1 inch was reported west and south of Baltimore, Martin said. Some accidents were reported throughout the region Wednesday night, but it was unclear if snow was a factor.
A storm dropping at least 18 inches would rank as one of the 10 biggest to hit Baltimore within a three-day span. More than 2 feet of accumulation would rank the storm in the top five, along with storms from February 2003, January 1996, January 1922 and the first of the back-to-back storms that hit in February 2010.
The forecast models meteorologists are using to predict the storm look eerily similar to those historic events, according to data gathered by Charles Graves, an associate professor of meteorology at Saint Louis University. Graves and colleagues developed a database in 2009 that compares forecasts to predictions made in the past, both as a tool to help meteorologists improve their forecasts and to gauge what sort of confidence they can have in their outlooks.
The set of scenarios the system produced this week to compare to the weekend storm have been getting a lot of attention on Twitter, Graves said, because they are the type, "from a meteorological point of view, that raise the hair on the back of your neck."
The most similar forecasts were made in February 1983, January 1996, February 2010 and December 2009 — right before storms that respectively rank fifth, second, fourth and 10th on Baltimore's all-time list of biggest snowfalls.