Warm, humid air is forecast to move over the region Thursday, pushing the heat index into the 90s and bringing chances for severe storms.
A tornado watch has been issued for Baltimore City, Washington, Harford, Frederick, Carroll, Baltimore and Allegany counties until 9 p.m. Storms capable of producing tornadoes were reported in southwestern Pennsylvania early Thursday afternoon.
The most significant threat of severe storms and of tornadoes is expected from northern Maryland, along the Mason-Dixon Line, into southeastern Pennsylvania, according to the Storm Prediction Center.
A flash flood watch is in effect until midnight for Baltimore City, Prince Georges, Baltimore and Anne Arundel counties.
A front that hung over the state Wednesday is forecast to lift northward on Thursday.
Intense humidity was in place, with dew points in the lower 70s making temperatures in the upper 80s feel like the lower 90s by the afternoon,
Clearer skies and seasonable temperatures are forecast Friday through the weekend, with highs in the mid- to upper-80s and lows in the upper 60s.