A squall line of rain showers could bring wind gusts of 40 mph or greater Friday afternoon, and significantly cooler air is behind it.
The line was moving into Central Maryland by 2 p.m. and was expected to cross the region by the evening rush hour.
It is bringing a short burst of heavy rain and strong winds, some of which could be strong, the National Weather Service cautioned.
After the burst of stormy weather, temperatures are expected to cool down quickly.
As of 2 p.m., it was 76 degrees and sunny at Baltimore/Washington International Thurgood Marshall Airport, but just 50 degrees and foggy at Garrett County Airport in Western Maryland, according to the weather service.
That sharp gradient between unseasonable warmth and cold extends up and down the East Coast, with afternoon temperatures in the 60s and 70s from Atlanta to Boston and in the 50s from Knoxville, Tennessee, to Pittsburgh and Rochester, N.Y.
Snow is possible Saturday in Western Maryland, while in the Baltimore region, temperatures are not expected to rise out of the 50s.
Many areas outlying Baltimore could see frost early Sunday morning.