If you get under one of these cells, it's intense. I received 0.64" of rain in 15 min from a cell today. Also, some of the mesonet soil moisture probes are showing fully saturated soils. For example, our flood sensor on Cabin John Branch at Bradley Blvd showed a 5 foot rise in 40 minutes on Saturday. If that storm over Potomac persisted for another 20 to 30 minutes it would have been real trouble.
This absolutely justifies the flood watches, IMO.