9:30 p.m. UPDATE: Forecasters are maintaining decent snow chances for Carroll County and along the Mason-Dixon Line in Baltimore and Harford counties, but for most of the Baltimore area, Wednesday night's system is expected to bring another dusting of snow.
Original post, as of 4:37 p.m.:
About 36 hours ahead of potential snowfall, forecasters were calling for at least an inch or two and possibly 4 inches of accumulation overnight Wednesday, according to the National Weather Service. As time passed Tuesday, though, confidence in that prediction was waning.
The weather service's Baltimore/Washington forecast office's forecast maps call for 1-2 inches across Baltimore, including southern Baltimore County and Howard County, with 2-4 inches in Carroll, northern Baltimore and Harford counties. South of Baltimore, an inch or less was expected. Those predictions were holding steady as of early Tuesday afternoon.
The forecasters expect rain early, turning to a wintry mix and then snow after about 9 p.m., tapering off by early Thursday morning. The heaviest precipitation could come after the air chills enough to support snow, according to the forecast discussion from early Tuesday morning:
"WARM NEAR SURFACE AIR MAY INITIALLY CUT DOWN ON SNOWFALL DURING THE DAYTIME ON WEDNESDAY...AND IT MAY TAKE UNTIL EVENING FOR AREAS /PARTICULARLY ACROSS THE NORTH AND WEST CWA/ TO CHANGEOVER TO SNOW. THIS WOULD HOWEVER COINCIDE WITH THE TIME WHERE THE BEST QPF MAY BE AVAILABLE AND WHERE A BAND OF AT LEAST MODERATE SNOWFALL MAY DEVELOP."
AccuWeather.com, meanwhile, included Central Maryland in an area that could get 3-6 inches by Thursday morning.