Commuters: This one will be icy
Maryland commuters, especially those who left for home too late last Wednesday and got stuck in the snow, should be paying attention to the weather forecast today. This is not going to be a big snow event. But the forecast for snow, sleet, and long periods of freezing rain are likely to affect the Tuesday morning commute. It's not something you can afford to shrug off.
Here's how Eric the Red is phrasing the outlook this afternoon: "This is really, really gonna suck, big, big time, especially in the counties along the PA border."
"...[F]or tonight, sleet and freezing rain, perhaps starting as a brief period of snow. Precip will be light, which when it comes to freezing rain is not good because the ice will stick to everything. Models agree northern Maryland is under the gun, but differ on DC. Plan on a hairy morning commute tomorrow, and be thankful if you wake up to bare pavement."
"Even close to DC and the Bay, Tues morn's commute may be greeted with freezing rain as well. Freezing rain will diminsh during the afternoon on Tues. ... Freezing rain and rain return in earnest Tues night into Weds morning, setting the stage for what could be a big-time ice storm across northern and western MD. Along the I-95 corridor, expect mostly rain Tues night into Weds, but this area will be right on the ice/rain edge."
The NWS has expanded the Winter Storm Watch to include Howard and Montgomery counties. It calls for snow and sleet developing tonight, changing to freezing rain overnight, with a quarter-inch 
of ice - or more - accumulating.
"INTERMITTENT AND LIGHT FREEZING RAIN IS POSSIBLE DURING THE DAY TUESDAY. ON TUESDAY NIGHT FREEZING RAIN IS EXPECTED TO INCREASE IN COVERAGE AND INTENSITY...AND CONTINUE THROUGH WEDNESDAY MORNING."
Forecasters don't expect the ice overnight tonight will warrant a Winter Storm Warning. But Tuesday night into Wednesday, higher precipitation amounts might eventually demand one.
The student forecasters at Foot's Forecast seem to agree: "High temperatures for areas further south across Central Virginia, Southern Maryland, and the lower Eastern Shore are expected to reach the mid 30s Tuesday, allowing any freezing rain early in the day to become all rain. Depending on the extent of cold air locked at the surface, areas near the Mason Dixon line into northern Delaware may experience an extended period of freezing rain into Tuesday night, with all rain for areas to the south."
The Tuesday night-into-Wednesday picture looks especially nasty. Eric lays it all out for you, on the jump:
"The second part of the storm is the main event, and this will arrive Tues night and last into mid-day Weds. Temperatures will be critical. The WRF/NAM [model] has a northeast wind locking in the cold air, and paints an ugly, ugly picture from northern MD into WV Tues night into Weds morning.
"As a bonus, the WRF also has freezing rain falling almost all the way to the Bay and northern DC until ~ 5 am on Weds, again courtesy of a bonus round of northeast winds Tues night into early Weds. The WRF liquid total is over an inch, and if it were to verify, would mean downed power lines and trees across much of the state.
"On the other hand, the GFS [model] does not hold the cold air in place quite like the WRF, so it would be a cold, heavy rain for much of the I-95 corridor Tuesday night, but would likely still have ice across northern and western MD. In short, the WRF would be awful, the GFS just merely unpleasant.
"Tues night - after midnight (we're gonna let it all hang down) - another round of freezing rain will arrive, but this will be heavy.
"Closer to I-95, the second round of freezing rain will probably change to cold rain relatively quickly, and Weds morning will hopefully not be too bad. Once you get into the Piedmont (west of I-95), it will be a different story... with heavy freezing rain lasting into the morning hours on Weds, perhaps changing to rain before ending mid day."
Comments
Actually, readers may be more interested in the projected NWS ice totals:
http://www.erh.noaa.gov/lwx/winterstorm/images/StormTotalIce.png
Posted by: Damion | January 31, 2011 2:20 PM
Frank,
We need to be careful. The models have initalized colder than in previous runs, and the NAM slows down the low, which lends support to the high in Canade becoming stronger than forecast and having more time to draw cold air into our region. It also sets up the WAA region a lot more nicely. With the high moving more cold air into the region and keeping it around longer, we could see even more freezing rain than forecast. Like Eric said, it all comes down to temps...and if this high is even a little stronger than forecast, we could see more freezing rain down towards DC.
Posted by: Sam | January 31, 2011 3:44 PM
Damion - Those ice totals are predicted through Tuesday at noon. So, Eric and Foot's may correct in their forecast because the Tuesday night-Wed. AM period is when they are forecasting the heavy period of freezing rain. It seems though, that this will come down to neighborhood by neighborhood depending on the temps.
Posted by: Carrie | January 31, 2011 9:24 PM