Details from AccuWeather.
There are already major flight delays (one hour or more) at Minneapolis, LaGuardia, and, for some flights, Chicago. These will likely get worse during the day.
UPDATE: Separately, San Francisco just posted average 1 hr. 6 min. delays due to low clouds.
2nd UPDATE: Speaking of San Francisco, my friend Jan Null states, During the past hour (5-6 am) downtown San Francisco’s seasonal rainfall total pushed past their “normal” full season (July 1 to June 30) amount of 22.28 inches. Currently the season to date total is at 22.41″ with rain expected off and on through Saturday.