Patch spoke Tuesday with meteorologist Calvin Meadows, who is with the Baltimore-Washington forecast office for the National Weather Service.

Here's a timeline of what to expect from the snow expected to hit late Tuesday and Wednesday, according to Meadows:

• Tuesday, 7-9 p.m.: Rain
• Tuesday-Wednesday, 10 p.m.-2 a.m.: Wintry Mix
• Wednesday, 2 a.m.: Snow
• Wednesday Morning: Wintry Mix
• Wednesday 10 a.m. - Midnight: Snow

A "rain-snow" line will determine which areas see more snow than others, Meadows said.

"Right now, the latest information indicates that west of 95, the best-case scenario is 5 inches of snow.... The worst-case is 12 inches of snow."

Meadows said to expect snow accumulation of 2-4 inches early Wednesday, with snow continuing Wednesday, with another 3-5 inches possible, and then tapering off by midnight Wednesday.

People who live east of Interstate 95, should expect to see snow—just not as much, he said. "[Expect] 1 to 3 inches tonight, and maybe another 2-4 inches during the day Wednesday," he said.

East of I-95 "it looks like they're going to get more rain mixed in," Meadows said. "On Wednesday, it'll warm enough to get rain mixed in and then it will switch to snow after 10 a.m."

Meadows said that Wednesday morning, there will be a lull in the storm, and it will "look like it's ending, and rain will mix in, and then we'll another batch of energy move through and we'll get some cooling aloft and it will change back over to snow again after 10 a.m."

How will the roads be? "The roads at least in the beginning, will be warm enough that snow will accrue more on grassy areas, than the pavement, but it may be the intensity, especially in the heart of the storm late tonight, will be such that it'll accumulate on the roads too," Meadow said.

Temperatures will be in the mid 40s Tuesday afternoon, dropping down into the low 30s Tuesday night, a little above freezing and then rise up into the mid 30s on Wednesday.

Any accumulating snow will start melting Thursday, when temperatures rise into the 40s under mostly sunny skies.