A "nor'easter" storm has the potential to bring 6 inches of snow or more Thursday across Central Maryland, but accumulations will depend on the storm's unpredictable path, forecasters said.
The National Weather Service placed nearly all of Maryland under a winter storm watch Monday, with 5 inches of snow possible from Wednesday evening through Thursday evening. Forecasting models suggest cold northern air will converge with Gulf of Mexico moisture off the Carolinas on Wednesday, sending a potent storm system northeast up the East Coast.
Where the storm's center falls relative to shoreline will help determine whether precipitation falls mostly in the form of heavy snow, or if rain or sleet cut down on snow accumulations.
"This is one of those storms where the path is hypercritical," said Keith Krichinsky, executive director of the online meteorology service Foot's Forecast. "I don't know anyone who's good enough to predict that."
Forecasters held off on making specific snow accumulation forecasts, but said most of the state could expect significant snowfall even if some rain and sleet mix in. Weather service forecasters cautioned of a "high-impact" storm with as much as 1.5 inches to 2.5 inches of liquid precipitation falling mostly as heavy, wet snow, with rain and sleet mixing in closer to the Interstate 95 corridor.
An inland storm track would draw in warmer air from over the Chesapeake Bay and Atlantic Ocean, making for more rain, while most or all precipitation could fall as heavy snow if the storm hugs the coastline, Krichinsky said.
The storm's strength could also mean blustery winds, with gusts up to 30 mph as the storm moves through, according to weather service forecasters.
The snow forecast was enough for Paul Wiedefeld, CEO of BWI Airport, to urge fliers leaving their cars at the airport in coming days to park in airport garages.
"Be in a garage. Don't be out in one of the surface lots," he said. "It makes it a lot easier for everybody."
The snow was expected to fall on top of an inch or two that accumulated Sunday and won't melt any time soon, with temperatures forecast to remain below freezing until the storm is forecast to arrive. Two inches of snow fell in Finksburg, with 1.5 inches in Cockeysville, 1.1 inches in Bel Air, 0.7 inches near Pimlico and 1 inch at Fort Meade, according to the National Weather Service.
Before it arrives in Maryland, the storm was expected to bring a second round of wintry precipitation in recent weeks to the southeastern U.S. In Georgia, where a couple of inches of snow recently caused gridlock and stranded motorists for hours, Gov. Nathan Deal imposed a state of emergency across much of the state. Winter weather advisories and winter storm warnings stretched from Texas to New Jersey on Monday, while the weather system was moving through California and Nevada.
Baltimore Sun reporter Kevin Rector contributed to this report.