Heavy fog forced a ground stop which was then upgraded to a ground delay and then another ground stop at Denver International Airport on Tuesday morning. The FAA ordered the ground stop because of the fog that settled into the Denver metro area.

ATLANTA — A ground stop has been issued for some departures to Hartsfield-Jackson Atlanta International Airport on Tuesday afternoon, amid severe thunderstorms and tornado warnings in the metro Atlanta region.

Thousands of flights across the U.S. were delayed Monday, as severe thunderstorms in the South, Plains and Mississippi Valley disrupted traveling Americans during the Memorial Day weekend. As of 4:30 p.m. EDT on Monday, there were over 4,300 flight delays and more than 125 cancellations in and out of U.S. airports, according to FlightAware.

That was the case this week on a Delta Air Lines flight I took from Grand Rapids to Minneapolis on my way to Mountain View, California, for Google I/O. Because of weather over parts of the Midwest, a thing that regularly disrupts travel in these parts, our flight was delayed at the gate for an hour or so.

AUSTIN, Texas — Some travelers going through the Austin airport Wednesday are being forced to wait after the Federal Aviation Administration (FAA) issued a ground delay for most of the day.