UPDATE: 3:14PM. Six minutes after posting the info below, the FAA posted average 1 hr. 15 minute delays for Atlanta Hartsfield.
UPDATE: 3:23PM: From 7News Boston. Earlier this afternoon taken at Logan Airport. Tornado warning was in effect. Do not know if it touched down.
Here is the latest forecast from the National Weather Service's Storm Prediction Center for severe thunderstorms the rest of today and into tonight. Fifteen percent is the "significant" threshold. Note the area of 30% along the Northeast coast.
Here is a summary of the situation using AccuWeather's regional radar as of 3:55pm EDT.
The sheer number of thunderstorms (closing down airspace for planes aloft) and the proximity of storms to so many major airports is causing huge delays for hundreds -- and likely now thousands -- of flights.
My Airline Crisis Survival Guide is here.
My colleagues at AccuWeather are live-blogging the storms. So, I'm turning coverage over to them.