Strong thunderstorms are now moving east of DC there are some precautionary warnings  Check Live Doppler   The storms will be around and through the metro area now until Midnight.  There are warnings as a precaution after the Derecho of 2 weeks ago. Very heavy rain and lightning but NO widespread wind damage. 

Later tonight and tomorrow a cool front will be to our north and with a wave of low pressure along the front, some heavy showers are likely to develop especially to the north of DC. 

The air is very moist for miles above us and any slow moving storms could cause some local flash flooding.  Finally by Saturday the front is a bit to the south and with east to northeast winds, a real break in the heat, but with cloudy, showery and almost cool conditions for folks heading to the beach