Classic issue when we have bad mid level lapse rates and dry air at the surface. Storms just can't get above 10,000 feet and the updrafts kick the storms apart.
Subtle surface boundary (bay breeze?) drifting west through Baltimore. Looks like the Towson and Baltimore City mesonet sites are showing a southeast wind, while everything else if firmly southwest. Might act as a focus for some better storms in a few hours.
It seems the storms are getting a bit of a boost from the mountains, then immediately dying off once they get on the lee side. With nighttime setting in, any remnant instability will likely wane quickly.