An inch or two of snow is expected across the Baltimore area Tuesday, with 2-4 inches possible in parts of Carroll, Baltimore and Harford counties.
A storm is expected to move up from the Carolinas, bringing precipitation from the southern Appalachians to New England. While a significant snowstorm is expected in Boston and on Cape Cod, the mid-Atlantic was expected to be spared of the heaviest precipitation.
Much of the snow could also fall while the sun is still up, which would likely limit accumulation to grassy surfaces.
The National Weather Service's Baltimore/Washington forecast office is calling for a 90 percent chance of snow Tuesday starting around mid-morning and continuing into the afternoon.
Temperatures were forecast to reach the upper 30s in the afternoon. That is about 20 degrees below normal for this time of year.
Weather service meteorologists wrote in forecast discussions that the storm is not expected to strengthen, in a phenomenon when two systems combine in what is known as "phasing", until after it has passed the mid-Atlantic. They suggest about a 60 percent chance in Baltimore and points north of at least 2 inches of snow, and a 30 percent chance of at least 4 inches of snow.
Forecasters at the national Weather Prediction Center in College Park say it remains uncertain, however, where the storm will track and where it will strengthen. The earlier the storm "bombs", when the pressure at its center plummets, and the further west it tracks, the more likely significant winter weather could occur in the Carolinas and mid-Atlantic, according to the center.
Models are suggesting it will stay far enough off the East Coast to keep the heaviest precipitation out to sea, according to forecast maps. But a more western track "cannot be discounted", forecasters wrote. Some factors determining how the storm behaves may not become clear until 12-24 hours in advance, they wrote.
Meteorology website Foot's Forecast emphasizes uncertainty that depends on the storm's timing. If the heaviest precipitation is delayed until Tuesday night into Wednesday, it could mean a snowy morning Wednesday.
AccuWeather.com's Henry Margusity suggests snow could fall from the southern Appalachians to New England, including across Central Maryland, with the Canadian model the only of the major forecasting models to suggest heavy snow along the Interstate 95 corridor. There could meanwhile be a risk of blizzard conditions in New England if the storm intensifies as it moves northeast.
"I hope this is the last of the very cold weather," Margusity adds.
This has already been Baltimore's snowiest March since 1993, with 11.7 inches measured at BWI Airport.