Confidence is building that a strong storm moving up the East Coast will dump a major snowfall across Maryland this weekend, but it's not a sure bet just yet.
The Weather Prediction Center in College Park, a branch of the National Oceanic and Atmospheric Administration, is predicting 1-2 feet of snow near and northwest of Interstate 95 from Washington, D.C., to New York.
The center said Tuesday morning it has "high confidence in a major winter storm."
The National Weather Service is forecasting snow, with some rain mixing in at times, from about midday Friday through Saturday night.
The combination of slow movement expected from the storm, plenty of moisture within it and cold air ahead of it "suggest that there is a potential for a major winter storm," forecasters wrote Tuesday afternoon. But the forecast is still uncertain because it's looking ahead four days, they cautioned.
The weather service's Baltimore/Washington forecast office has upgraded its warnings for a winter storm threat from "moderate" to "high," cautioning of significant travel delays, closures, and threats to life and property.
AccuWeather.com echoed those concerns, saying winds could be intense along with the snowfall.
"If the storm develops to its full potential and takes a track just off the mid-Atlantic and New England coasts, then a blizzard can unfold," AccuWeather forecasters wrote. "The storm could shut down highways and perhaps cause airport closures."
Thunder and lightning could accompany the snow, according to AccuWeather, a phenomenon known as thundersnow.
Foot's Forecast is predicting a historic storm.
"If computer model trends continue in the manner they have shown since Friday 1/15, there is potential to see impacts that could equal that of events in January 1996 and February 2010," Foot's forecasters wrote.
Forecasts could change in the coming days, though. The system that is expected to become the storm was crossing from the Pacific into California on Tuesday. It's still too early to make specific snowfall accumulation forecasts.
"A shift in the storm track by 50-100 miles farther north would allow precipitation to become mixed with or change to rain in the I-95 corridor," AccuWeather wrote. "A more northerly track would push the heaviest snow across the central and northern Appalachians."
Foot's Forecast leaves a 30 percent chance that the storm develops more slowly and stays to the south of Maryland before moving out to sea, which could just mean some light snow across Maryland and Virginia on Friday.