Wind gusts surpassed 40 mph Thursday around Baltimore, making it feel like the single digits outside. Before the cold departs for the weekend, an icy winter storm could hit northwestern suburbs.
A winter storm watch is in effect in Washington, Frederick, Carroll and northern Baltimore counties from late Friday night through Saturday morning. Up to an inch of snow and ice followed by as much as a quarter of an inch of freezing rain are forecast.
Frigid air is blowing into the region from the northwest. A gust reached 46 mph at Baltimore/Washington International Thurgood Marshall Airport at 8:05 a.m. Thursday, according to the National Weather Service.
Other reported gusts included 55 mph in Brooklyn Park, 48 mph in the McDonogh area near Owings Mills, 47 mph near Westminster and 46 mph near Edgemere.
With air temperatures hovering in the lower to mid-20s, the wind chill remained in the single digits through Thursday afternoon.
It peaked around 1 p.m., when the air was 24 degrees and a 21 mph wind made it feel like 9 degrees. By 4 p.m., the wind chill fell to 3 degrees, with an air temperature of just 20 degrees and unrelenting winds.
The wind chill value is based on a complicated equation that factors in air temperature and wind speed. The perceived chilling effect of any gust of wind is different depending on the temperature — the colder the air, the larger the chilling effect of wind.
Temperatures are expected to peak around 25 degrees Thursday afternoon, several degrees colder than normal lows for this time of year.
A wind advisory is in effect through 3 p.m. Winds from the northwest are expected at a steady 20-30 mph, with gusts up to 50 mph possible.
Lows are forecast to drop to the lower teens overnight into Friday morning. With 10-15 mph winds forecast through the night, it could feel as cold as 1 degree below zero, according to the weather service.
The frigid Arctic air that blew in behind a cold front overnight is also remarkably dry. The dew point was several degrees below zero, meaning that the air would have to get that cold for dew to form.
Area health officials opened warming shelters and urged people to check on homeless and vulnerable people. Baltimore Health Commissioner Dr. Leana S. Wen issued a Code Blue advisory from Wednesday night through noon Friday.
Three people died of cold-weather-related causes such as hypothermia in Maryland last year, state officials said. They urged residents to bundle up with hats, scarves and mittens instead of gloves, and to take care when using portable heating sources that can give off carbon monoxide.
The cold spell is expected to end with a period of snow and ice Friday night into Saturday morning. But then, a dramatic warming is expected, with highs around 50 Saturday and possibly the mid-50s Sunday.