Another severe thunderstorm warning was in effect for D.C., Montgomery County, Maryland, the City of Falls Church, the City of Alexandria and Arlington and Fairfax counties in Virginia until 8:15 p.m.
Golf ball-sized hail and winds up to 60 miles per hour are potential risks, according to the outlook.
More severe thunderstorm warnings are likely to trickle through as the evening progresses, Theodore said.
The storms are moving east at 25-30 miles per hour, and the highest risk of severe weathers will be northwest of I-55 between 4 and 8 p.m., with hail and damaging winds the primary hazards, NWS said.
Residents are asked to follow all instructions from emergency services officials and signs to keep lanes clear for emergency vehicles.
There is a flood warning for Wicomico and Worcester Counties until 9 a.m. Sunday. For a complete depiction of the watch see the associated watch outline update (WOUS64 KWNS WOU9).PRECAUTIONARY/PREPAREDNESS ACTIONS.REMEMBER.A Severe Thunderstorm Watch means conditions are favorable for severe thunderstorms in and close to the watch area.
Meteorologists say the storm is capable of producing large hail, damaging winds and frequent lightning.
A corresponding Hazardous Weather Outlook has been issued for the same counties, as well as Lake, Porter, Newton and Jasper counties in IN, according to the weather service.