Official forecast leans to rain, changing to snow
National Weather Service forecasters out at Sterling seem to be moving toward a more confident prediction for this week's winter storm. They're talking about a largely rain event for the I-95 corridor, but one that will likely see some changeovers to wet snow, with a snowy finish.
It's not all in the bag yet. There remains some considerable uncertainty about the precise storm track. And, as usual, only a small movement in the rain/slop/snow line could make all the difference for the densely populated I-95 corridor.
The official forecast for BWI-Marshall Airport calls for a 40 percent chance of rain or snow beginning after midnight Wednesday morning. That would become all rain after noon on Wednesday, with daytime highs in the upper 30s. Rain and snow chances remain at 60 percent into Wednesday night, changing to all snow after midnight. Overnight temperatures would drop into the upper 20s.
The action here is centered on a storm dropping out of the Rockies and developing on the Texas Gulf coast today. It will move east, gathering up lots of Gulf moisture and sending it north and east into the Southeast and mid-Atlantic states. Delays in that movement are expected to allow the arctic high-pressure system that's been making us so cold this weekend to move out of the way, moving our temperatures to moderate before the rain from the South gets here.
After that initial rain on Wednesday, NWS forecasters said: "THE SECOND PORTION OF THE SYSTEM...MOVES UP FROM THE SOUTHERN APPALACHIANS AND UP ACROSS THE CAROLINAS AND OFF THE VA TIDEWATER. AROUND THE BACKSIDE OF THE UPPER LOW WOULD BE DECENT
COVERAGE OF PRECIP AND W/ THE COLD AIR WRAPPED AROUND THE UPPER LOW
- BETTER CHANCES FOR WINTRY PRECIP /MAINLY SNOW/ ACROSS THE AREA
BEFORE THE FEATURE DRIFTS OFF THE COAST LATE WED NIGHT."
AccuWeather.com's Brian Edwards this morning notes the potential for a significant snowstorm here if the storm tracks just right, but then concedes that is now less likely:
"A track just off the coast would bring the heaviest snow to the I-95 cities and the beaches, as we have seen before, thus sparing the Appalachians the worst ... It seems less likely at this point for a major snowstorm along the I-95 corridor from Washington, D.C., to Philadelphia and New York City and along the Eastern Seaboard Tuesday night through Wednesday night.
"The brutal arctic cold that has been in place will be eroded on Tuesday as an area of high pressure retreats and a southeasterly flow off of the Atlantic Ocean pulls in milder air."
Foot's Forecast offers four scenarios this morning, but favors Scenario A: "The storm tracks along the coast Wednesday, bringing a mixture of rain and snow for the immediate I-95 corridor from Washington, D.C. to Philadelphia. Some snow would be possible for areas west of I-95 in western Maryland and western Virginia. Areas from Southern Maryland to the upper Eastern Shore would have a mix of rain and snow or just rain, with all rain for the Atlantic beaches. Liquid Precipitation totals for the I-95 corridor could exceed one inch in some places, however light snowfall amounts would be confined to a possible changeover to snow on the backside of the system."
We'll see. In the meantime, we are emerging from another very cold night on the WeatherDeck in Cockeysville, with a morning low at dawn today of 2 degrees. It's 7 degrees as I write this at 9 a.m.
BWI-Marshall reported a low of 8 degrees around 7 a.m. today. The record low for the date is 1 degree, recorded in 1963. The low at The Baltimore Sun's weather station, Calvert and Centre streets, was 16.7 degrees. Here (on the jump) are some other 7 a.m. readings from around the area. Feel free to report your lows in a comment.
Maryland Science Center: 17 degrees
Reagan National: 18 degrees
Dulles International: 6 degrees
Annapolis: 18 degrees
Martin State Airport: 12 degrees
College Park: 12 degrees
Westminster: 9 degrees
Hagerstown: 8 degrees
Cumberland: 7 degrees
Oakland: 9 degrees
Salisbury: 9 degrees
Ocean City: 13 degrees.