(From the Maryland Weather blog)
With an ice storm on deck for Tuesday, the National Weather Service has posted a Winter Storm Watch for the northern tier of Maryland counties, from Garrett in the west to Cecil in the east, and including Baltimore City.
The Watch begins late Monday night and continues through WEDNESDAY morning. As much as a quarter-inch of ice could accumulate Tuesday on branches and utility lines, meaning a risk for another round of power outages for a region that only emerged this weekend from the last round.
For the northern counties, the event is forecast to begin late Monday night with snow, sleet and freezing rain as temperatures rise overnight out of the mid-20s. That is expected to change over to all freezing rain Tuesday morning, continuing straight through until early Wednesday, when it will finally become just rain.
"A WINTER STORM WATCH MEANS THERE IS A POTENTIAL FOR SIGNIFICANT SNOW...SLEET...OR ICE ACCUMULATIONS THAT MAY IMPACT TRAVEL. CONTINUE TO MONITOR THE LATEST FORECASTS." - NWS
South of those counties - from Montgomery, Howard and Arundel south - the weather service is calling for a confection they're calling "a light wintry mix," including some freezing rain. We may AccuWeather.comsee them issue a Winter Weather Advisory later today to cover some "light" ice accumulations. The precipitation would change to rain Tuesday afternoon.
The culprit is another storm system, this one now developing in the Plains. As it approaches, it will throw warmer, wetter air into the region from the southwest, That air will be forced up and over the very cold layer of air now resident east of the mountains - cold air damming.
The precip could begin as snow in the northern counties, but once it starts falling, whatever falls will gradually erode the cold air, changing to sleet and freezing rain. Forecasters give the counties near the Mason-Dixon Line the best chance to see freezing rain persist through the day Tuesday and into Wednesday morning.
The whole mess should pass by Wednesday afternoon. A Wednesday high of 47 degrees will give way behind the passing cold front to a resumption of below-average cold temperatures for the balance of the week, with highs in the low 30s.
Don't you just love winter?
The good news is that this round of bad weather is actually the good side of this storm. Portions of the Central Plains and the Midwest are facing heavy snow, even blizzard conditions, this week as the Groundhog Day storm blows through. Here's AccuWeather.com's take. Punxatawney Phil seems unlikely to see his shadow.