JFK, LaGuardia, Newark, and Philadelphia are now under ground delay programs on a ZNY staffing constraint, with LaGuardia also ground-stopped and O'Hare and Midway re-stopped by a line of storms overhead

The same-day update: the New York ground delay programs the FAA was still convening at 11:54 AM are now live and the FAA's own advisory attributes them to a ZNY staffing constraint compounding the thunderstorms, LaGuardia took a ground stop with all N90 west gates closed, O'Hare and Midway caught fresh ground stops from a line of storms now overhead the fields, Austin is under a disabled-aircraft ground stop, JFK arrivals are averaging 2 hours 29 minutes, O'Hare departures are averaging 1 hour 45 minutes, the watch runs to Miami and Fort Lauderdale after 3 PM ET and Denver after 5 PM ET, and Delta's New York City weather waiver covers July 27-28 travel.

The New York programs this morning's issue flagged as "convening" have all gone active. The FAA's operations plan advisory ADVZY 096 (event time 27/1800Z and later, in effect at delivery) issues escape routes for Boston, N90, and Philadelphia alongside ground delay programs for Newark, JFK, LaGuardia, and Philadelphia, and states the cause plainly: "DUE TO ZNY STAFFING CONSTRAINTS." A separate LaGuardia ground stop was issued for thunderstorms, and the FAA notes "N90 BRIEFED THAT ALL WEST GATES ARE STOPPED FOR THUNDERSTORMS." A NY Metro holding advisory and diversion recovery are active. The live delay picture: the FAA's own JFK airport status page (last updated Jul 27, 2026 at 6:58 PM UTC, 2:58 PM ET) reports a traffic management program "Due to STAFFING / STAFFING" delaying arriving JFK flights an average of 2 hours and 29 minutes, with airborne arrival delays of 15 minutes or less. FlightAware's LaGuardia page (2:58 PM EDT) shows departure delays averaging 28 minutes and increasing, and LaGuardia's METAR at the same time reports a cumulonimbus cloud overhead moving east with vicinity showers. The Mirror US (published 1:51 PM ET today) independently confirms the LaGuardia ground stop and the JFK staffing-driven delays, and notes Delta Air Lines saw the most cancellations out of LaGuardia as of Monday morning. The four programs run deep into the night: Newark until 11:29 PM ET, LaGuardia and Philadelphia until 11:59 PM ET, and JFK until 12:59 AM ET Tuesday. Delta's New York City Thunderstorm advisory covers July 27-28 travel through EWR, JFK, LGA, and White Plains with rebooking open through July 31, the one confirmed carrier waiver for today; no United or American July 27 storm waiver was live as of this run, so travelers on those carriers should check the United travel notices and American travel alerts pages directly.

O'Hare and Midway are back under ground stops. ADVZY 096 lists both "ORD AND MDW GROUND STOPS ISSUED DUE TO THE LINE OF THUNDERSTORMS THAT ARE CURRENTLY OVERHEAD THE AIRPORTS," set until 2:15 PM ET. This sits on top of the O'Hare ground delay program filed in the late morning (averaging 132 minutes with a 205-minute maximum, per the CDM GDP proposal) that continues through 10:29 PM ET. FlightAware's O'Hare page (2:58 PM EDT) reports arrival delays averaging 1 hour 18 minutes and decreasing, with departure delays averaging 1 hour 45 minutes and increasing. O'Hare's METAR at 1:51 PM CDT captured the cell moving through: occasional lightning and cumulonimbus distant east and southwest-northwest moving southeast, a wind shift at 12:59 PM, and a peak gust of 26 knots, with the terminal aerodrome forecast calling for temporary variable winds gusting 35 knots and heavy thunderstorm rain through the early afternoon. The Enhanced Risk severe-storm day the Storm Prediction Center posted over the southern Great Lakes is now producing the convective line the morning forecast warned about.

Austin-Bergstrom is under a separate, non-weather ground stop until 2:30 PM ET for a disabled aircraft, per ADVZY 096. That is a transient airfield problem, not the convective system, but it adds one more metered arrival queue on a day when the eastern half of the country is already tight.

The watch now runs east and south. ADVZY 096 keeps Miami and Fort Lauderdale flagged for possible ground stops after 3 PM ET and Denver after 5 PM ET, with Boston, Philadelphia/Newark/Teterboro/MMU, BWI/Reagan/Dulles, and Orlando/Tampa all possible through 10 PM ET. A Tampa operations staffing trigger runs 4 to 9 PM ET. Terminal constraints list vicinity thunderstorms at N90, Philadelphia, Potomac, Atlanta, Florida, Chicago C90, Detroit, and Denver, with low ceilings at Charlotte, Southern California, Seattle, and San Francisco (where the chronic construction ground delay program runs until 6:59 PM ET). The next FAA planning webinar is at 3:15 PM ET, and the advisory names VIP movements departing Pontiac after 4 PM ET and arriving Andrews after 5 PM ET, which can compound the Detroit and Washington arrival gates already in the thunderstorm cone.

Rebooking basics

Delta's New York City Thunderstorm advisory is the active waiver: original travel July 27-28 through EWR, JFK, LGA, and White Plains, rebook through July 31 in the same cabin and city pair. United and American had not posted a July 27-specific waiver as of this run; open United's travel notices and American's travel alerts to check whether one posts after the 3:15 PM ET FAA planning call. For live status, the FAA NAS status page and the FAA advisory specialist page are the primary sources, and FlightAware's airport pages track the per-airport delay and cancellation counts.