The Storm Prediction Center has placed all of Maryland, Delaware, New Jersey, West Virginia, Northern Virginia, and parts of Pennsylvania under a Slight Risk (Level 2) for scattered strong to severe thunderstorms during the afternoon and early-evening hours. The biggest threats to watch out for will be damaging winds, large-sized hail, and heavy rain which could potentially lead to localized flooding depending on how fast the storms travel.
A stalled out boundary with keep the hot and humid air mass around the Mid-Atlantic region, which will prime the viewing area for severe thunderstorm activity this afternoon. The environment is very favorable for more organized showers and thunderstorms to develop and that is what the HRRR shows. The storms will start to spark up during the afternoon hours through dinnertime.
The timeline for severe storms will be between 3 PM - 9 PM. Showers and storms will start to diminish around sunset. The chance of storms redeveloping is low but not zero. There will be shower and thunderstorm chances in the forecast for Thursday.