The Brief Thunderstorms prompted a ground stop at O'Hare Airport Friday morning, halting landings and departures around 8:30 a.m., according to the FAA. The ground stop is expected to last until 9:30 a.m., with nine flights canceled so far and average delays under 15 minutes. A ground stop was issued at O'Hare Airport Friday morning due to weather. What we know:Thunderstorms prompted the Federal Aviation Administration to halt landings and departures at O'Hare Airport around 8:30 a.m. The ground stop is in effect for O'Hare until 9:30 a.m.