A Flash Flood Watch is in effect for much of Northern and Central Virginia through late this evening. A stalled boundary near the area is responsible for pulling in tropical-like moisture across portions of the Mid-Atlantic Region. Rainfall rates this afternoon and evening could be on the order of 1 to 2 inches per hour. The Weather Prediction Center has a MODERATE RISK for excessive rainfall across all of Northern Virginia.
TIMING of the heaviest rain will occur between 3 p.m. this afternoon through 10:00 p.m. this evening. Some locations across Northern and Central Virginia could see isolated rainfall amounts up to 4 inches. The ground remains fairly saturated and this amount of rain will likely cause creeks and streams to rise rapidly and flood across area highways and produce flash flooding across low lying and poor drainage areas. If you approach a flooded highway, TURN AROUND, DON’T DROWN. Six inches of water will reach the bottom of most vehicles and one foot of water can move a vehicle. Never take that risk as you never know how deep the water may be.
For locations south of Interstate 64, thunderstorms will be widely scattered. Isolated flash flooding is possible, however, the threat is much lower.