A winter storm warning is in effect across Central Maryland on Wednesday, bringing as much as 5 inches of wet, heavy snow and chances for a tenth of an inch of ice or more.
The National Weather Service is calling for “heavy mixed precipitation” throughout Wednesday. Snow arrived in the morning hours and continued into midday, but was forecast to change to sleet, freezing rain and finally rain in the late afternoon and evening as a layer of warmer air moves in overhead.
The timing of that transition to ice and rain will be key to how much snow and ice actually end up accumulating, weather service forecasters said. But regardless of when that occurs, they warned of a “significantly impactful” storm and “very difficult” travel conditions during both the morning and evening commutes Wednesday.
By about 1 p.m., as much as 5 inches of snow was reported around Baltimore and in parts of Howard and Carroll counties.
[ Live winter storm updates: Snow totals, travel conditions and more ]
Meteorologists are forecasting snow totals of 3-6 inches along the Interstate 95 corridor, with slightly less to the south and east, and more to the north and west. The agency predicted a 10 percent chance the storm could produce as much as much as 8 inches in Carroll County.
The storm winter warning is in effect through 7 p.m. in Baltimore, southern Baltimore County, southeast Harford County and Anne Arundel County, and through 10 p.m. in Howard and Carroll counties and northern portions of Baltimore and Harford counties.
The weather service predicted sleet would start mixing in by early afternoon.
Once precipitation changes over to sleet and freezing rain, ice accumulation approaching a tenth of an inch is forecast west of Interstate 95, particularly across higher elevations of Baltimore, Carroll, Harford and Howard counties, where cold air is forecast to linger for longer. A glaze of several hundredths of an inch of ice is expected along the I-95 corridor.
Temperatures dropped into the upper 20s as snowfall began Wednesday morning, but were expected to slowly rise to the lower 30s by late afternoon. They are not forecast to rise above freezing until after sunset, reaching the mid-30s overnight, with rain expected through the night.
Additional rain and snow melt later in the week could lead to flooding of rivers and creeks Saturday night into early next week, the weather service said.
All public school systems across the state had canceled classes Wednesday, as did many private schools and colleges in the area.
[ Full list: School closings and delays ]
Interim Baltimore Health Commissioner Mary Beth Haller declared a “Code Blue” advisory for Wednesday, urging people to seek shelter and to check on elderly or vulnerable neighbors and relatives.
Gov. Larry Hogan urged Marylanders to stay home Wednesday, given that he expects “significant accumulations in a really short period of time.” He said State Highway Administration crews are taking the storm “very seriously” and spent Tuesday pretreating roads around the state.
The SHA announced shortly before 5 a.m. that nearly 1,700 pieces of equipment are deployed to treat its roads.
“This is going to be a dangerous storm,” Hogan said while visiting a State Highway Administration facility near Annapolis on Tuesday afternoon. “In spite of our efforts, we are going to have difficulty on the roads. So we want to encourage you, if possible, to stay home tomorrow while we clean up these roads.”
Walking could be dangerous, too. The weather service said that when venturing outside, residents should be careful on steps, sidewalks, and driveways, which could be icy and slippery, resulting in falls.
Officials at Baltimore-Washington International Thurgood Marshall Airport warned travelers to check with their airlines for information on delays or cancellations. Southwest, Delta, American Air and United airlines are among the carriers issuing travel waivers Wednesday, according to airport officials.
BWI is using about 270 pieces of snow removal equipment to help clear the airfield, parking lots and other surfaces, airport officials said in a tweet.
Foot’s Forecast predicts a widespread 4-6 inches of snow across Central Maryland, with lesser amounts across Southern Maryland and the Eastern Shore and as much as 10 inches across Western Maryland. Forecasters suggested heavy snow could last for 8 to 10 hours. Icy precipitation could follow for an additional six or eight hours, and then a cold rain is expected overnight into Thursday morning.
The combined weight of snow, sleet and freezing rain could result in downed branches and isolated power outages, the weather service said.
The Washington Metro announced service changes in advance of the storm.
Metrorail service will operate every 12 minutes on each line Wednesday to allow deicing equipment to operate between passenger trains and to match significantly reduced ridership demand in the morning. Service levels may be increased during the day if conditions allow.
Metrobus will begin Wednesday under the Severe Snow Service Plan. Under the severe plan, buses provide limited service on major roadways only. Many bus routes do not operate when a severe plan is in effect.
Winter storm warnings were posted Tuesday from the mountains of western North Carolina through parts of West Virginia and western Virginia and into southern Pennsylvania, as well as in the northern Plains states. Winter weather advisories stretched from northern Texas to the Great Lakes. And Flash flood watches were meanwhile issued across the lower Mississippi and Ohio valleys.
AccuWeather.com forecasters said as many as 200 million Americans could see ice or snow Tuesday or Wednesday, from the southern Plains states to the Great Lakes states to New England. In Southern states on the warmer side of the storm, flooding rain is predicted. In all, 39 states could be affected by the storm, AccuWeather said.