Storms could bring damaging wind gusts, flash flooding and possibly tornadoes Thursday night into Friday morning.
Storms, some of them severe, began moving through the region about 3 p.m.
Lightning struck a tree that was touching a house in the 200 block of Marlyn Avenue in Essex, sending a jolt of electricity into the house, Baltimore County fire officials said. While one person in the house was transported to a local hospital, it was for medical reasons not related to the lightning, officials said.
Earlier in the day, a tornado was sighted near Easton and Trappe in Talbot County just before 1 p.m.
With plenty of moisture in the air and instability in the atmosphere, any showers or storms could be capable of developing intense rainfall, at rates of an inch or two per hour, the National Weather Service cautioned.
The storm systems could be large and complex, and could bring a risk of more tornadoes and damaging wind gusts, the weather service's Storm Prediction Center said.
Temperatures reached 95 degrees at Baltimore/Washington International Thurgood Marshall Airport just before 2 p.m. Thursday. It was a fourth consecutive day at or above that mark at the airport, and an eighth-straight day in the 90s.
Temperatures fell nearly 20 degrees at the airport as storms passed Thursday afternoon, falling from 93 degrees at 3 p.m. to 76 degrees by 5 p.m.
The region was under a severe thunderstorm watch and a flash flood watch, but those alerts expired.
Starting Friday and into early next week, a cool-down to seasonable highs in the 80s is expected.
Stormy weather is expected to linger, with strong storm chances Saturday and Sunday and slight chances Monday.