The FAA's Air Traffic Control System Command Center publishes an operations plan for the national airspace and updates it through the day after planning calls with airlines and air traffic facilities. It lists the traffic management actions the FAA expects might be needed, like "EWR/LGA GS POSSIBLE AFTER 2000Z".
How to read an entry
- EWR/LGA: the airports involved.
- GS: ground stop. You'll also see GDP (ground delay program), AFP (airspace flow program) and others.
- POSSIBLE / PROBABLE / EXPECTED: how likely the planners think it is, from "might happen" to "very likely".
- AFTER 2000Z: when. Times are in Zulu (UTC).
Converting Zulu time
Subtract 4 hours for Eastern, 5 for Central, 6 for Mountain and 7 for Pacific during daylight saving time (add one more hour to each in winter). So 2000Z is 4 pm Eastern in summer.
Planned right now
- DEN GROUND STOP/DELAY PROGRAM POSSIBLE (AFTER 1400Z)
- BOS GROUND STOP/DELAY PROGRAM EXPECTED (AFTER 1500Z)
- MIA/FLL GROUND STOP POSSIBLE (AFTER 1500Z)
- SEA GROUND STOP/DELAY PROGRAM POSSIBLE (AFTER 1500Z)
- ORD/MDW GROUND STOP/DELAY PROGRAM POSSIBLE (AFTER 1800Z)
GroundStop.app shows these as orange dots on the live map, separate from active ground stops in red.
What to do
If your destination has a possible ground stop, keep an eye on your airline app and our airport page (for example Newark). If you have flexibility, an earlier flight can sometimes avoid the window. If it becomes an actual ground stop, see what to do next.