Baltimore appears in for its largest snowfall in at least two years. A storm that has dumped as much as a foot of snow across much of the northern Plains and Midwestern states is due to reach the mid-Atlantic overnight Tuesday. Stay tuned here for forecast updates Tuesday.
5:18 p.m.: National Weather Service forecasters said a tricky rain/snow line and surface air temperatures expected to be slightly above freezing could limit accumulations along Interstate 95. But to the north and west, intense bands of snowfall could form.
“Baltimore, kind of like D.C., they’re kind of right on the edge of getting rain and snow during the day,” said Steve Zubrick, science and operations officer for the weather service’s Baltimore/Washington forecast office in Sterling, Va. “It’s just so close.”
The relatively warm temperatures are expected to help contribute to wet, clumpy, sticky snowflakes that could weigh down trees, tree limbs and structures, he said.
That along with 35+ mph wind gusts had BGE readying 1,500 utility employees and 650 out-of-state workers. Utility officials use past storm experiences and predictive algorithms to estimate the magnitude of outages a storm might cause, said utility spokeswoman Rachael Lighty. The utility is readying for the possibility of several hundred thousand outages.
“We can plan as much as we want, but the weather is crazy and it can change at any minute,” Lighty said. “We do the best we can but we definitely hope for the best-case scenario but make sure we’re prepared for the worst.”
2:56 p.m.: The National Weather Service has issued a winter storm warning for the Baltimore area, though meteorologists meanwhile cut back their snowfall forecasts to 4-6 inches in areas north and west of I-95.
The warning covers Carroll, Baltimore, Harford and Howard counties and Baltimore City and calls for 4-8 inches across the region, with the higher totals toward the north and west. Precipitation is expected to start as rain and a wintry mix Tuesday night, turning to wet snow Wednesday morning, heavy at times.
Winds are meanwhile expected to be strong, with a 15-25 mph breeze and gusts up to 35 mph.
Anne Arundel and Prince George's counties are under a winter weather advisory, with 2-4 inches of snow accumulation expected over the duration of the storm. Precipitation is expected to taper off across the region Wednesday evening.
12:23 p.m.: The National Weather Service's Weather Prediction Center in College Park is calling for strong chances of at least 4 inches of snow for the west side of I-95 both Tuesday night and Wednesday.
The region has a 40-50 percent chance of at least 8 inches of snow and a 20-30 percent chance of at least a foot of snow, according to the center's forecast maps.
The storm is in some ways similar to those that have brought light dustings a few times this winter, explains the Weather Underground's Jeff Masters. It is a storm known as an Alberta Clipper, which typically move quickly from their origins in western Canada.
But unlike those storms, some of which came through the Baltimore area when overnight lows were in the lower teens in January, the air is warmer this time.
"Since warm air can hold more moisture, this Clipper is bringing heavier snowfall amounts than is usual for a Clipper," Masters wrote.
Possible warming temperatures can, of course, cut the other way in terms of snow accumulations. AccuWeather.com's latest forecast maps called for 3-6 inches over the I-95 corridor and 6-12 inches to the west of that.
11:13 a.m.: If there is any concern about the snow forecast busting, it's because temperatures could be on the edge of freezing, putting parts of the region on the warm side of the rain/snow line.
AccuWeather.com's Henry Margusity tweeted Tuesday morning that the latest runs of a U.S. government forecast model shows a lot of rain mixing in after snow falls early Wednesday.
Foot's Forecast also acknowledged that possibility.
"We are watching the potential for east winds to bring in warmer air off of the Bay around midday Wednesday, which could cause some areas to re-mix with or change to snow," Foot's meteorologists wrote Tuesday.
On the other hand, some unknowns could mean current snowfall estimates end up being too conservative, Foot's added. Localized bands of heavy snowfall could form in some areas, or the storm could stall over the region.
10:36 a.m.: Forecasts that have been waffling for days are aligning on a significant snowfall event for the mid-Atlantic with snowfall possible from Philadelphia and New York to tidewater Virginia and the Carolinas. For the Baltimore area, the divide between the snow haves and have-nots could be narrow, but most of the region is in for at least 6 inches, according to the National Weather Service.
Precipitation is expected to move in as rain or a wintry mix after about 8 p.m., turning to snow overnight. That transition could take a bit longer for areas south of Baltimore and along the Chesapeake Bay, tempering accumulations there.
A winter storm watch was in effect for Central Maryland from Tuesday night through Wednesday night, with 5 inches or more of snow cautioned.
Snow is forecast to be heavier to the west of Interstate 95, at 8-10 inches for most of the Baltimore suburbs. The city and areas east of I-95 and along the Chesapeake Bay could still be in for 4-8 inches, according to the weather service.
Local meteorologist "Eric the Red" said Tuesday morning that a slight warming in the forecast could lessen snowfall totals in those eastern areas, with more rain mixing in with the snow. On the Piedmont, west of I-95, some models are forecasting snowfall rates of as much as an inch an hour, he said.
Baltimore-Washington International Airport is in an area forecast for 6-8 inches of snow, so it could be a close call whether the snowfall is the heaviest on record for Baltimore since 2011 or 2010. At the airport, 7.6 inches of snow fell Jan. 26, 2011. The heaviest before that was the 15.5 inches in the second round of back-to-back storms during "Snowmageddon", on Feb. 10, 2010.
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