LaGuardia's ground delay program went live, Denver worsened to 2 hours and extended to midnight, and Salt Lake City entered a ground stop

The 9 PM Wednesday update: the 6 PM issue's LaGuardia "imminent" watch fired as a 43-minute ground delay program running to 11 PM ET, Denver's GDP worsened from 1 hour 18 minutes to 1 hour 56 minutes and extended an hour to midnight, Salt Lake City entered a thunderstorm ground stop, Las Vegas was downgraded from a possible staffing ground stop to TBFM-managed delays, San Diego joined the overnight GDP list, Orlando's ground stop expired but departure delays hit 3 hours, and JFK and Philadelphia are on time.

What changed: LaGuardia's GDP fired

The 6 PM issue said a LaGuardia program was "imminent" for throughput and surface congestion. It fired. FAA advisory ADVZY 182 (signed 7:39 PM ET, after the 7:15 PM planning webinar) lists a LGA ground delay program running until 0259Z (10:59 PM ET). The cause is a combination: surface constraints at LGA, Jacksonville Center (ZJX) airways closed for weather, and additional delays from an airspace flow program. The FAA is working with ZJX to open gates for LGA or provide relief on ground-delay assignments.

Flightcheck.live (FAA NASSTATUS feed, checked 9:18 PM EDT) shows LGA with a 43-minute ground delay average plus 30-to-44-minute departure delays due to weather. The FAA's LGA airport page confirms a traffic management program is in effect for arrivals due to weather and thunderstorms, with SWAP departure gate holds of 15 to 29 minutes and decreasing.

JFK is on time. The broader Northeast, which was the story for five issues Tuesday into Wednesday morning, has cleared except for LGA. Philadelphia, DCA, IAD, and BWI are all on time per flightcheck. Newark has 1-hour-to-1-hour-15-minute departure delays from weather but no ground stop or GDP. Teterboro has the same 1-hour-to-1-hour-15-minute weather departure delays.

Denver worsened and extended

Denver's ground delay program, which the 6 PM issue reported at a 1-hour-18-minute average running to 11 PM ET, has gotten worse on both measures. ADVZY 182 extended the program from 0259Z to 0359Z (10:59 PM to 11:59 PM ET), and flightcheck.live now shows DEN averaging 1 hour 56 minutes due to thunderstorms, up 38 minutes from the 6 PM reading.

The Denver Post reported that Tuesday's Denver GDP (the prior day's event) delayed 925 flights and canceled 40 by 7:25 PM, with the FAA program averaging 103 minutes. Wednesday's program is running longer and at a higher average than Tuesday's, though the thunderstorm pattern over the Front Range is the same mechanism: storms build along the mountains, reduce arrival capacity, and the GDP holds inbound flights at their origin airports to keep airborne holding minimal. The advisory lists ZDV Area 5 staffing as a compounding factor until 0200Z (10 PM ET), alongside the weather.

Salt Lake City entered a ground stop

Flightcheck.live (checked 9:18 PM EDT) shows a ground stop at Salt Lake City International due to thunderstorms, expected to end at 8:30 PM Mountain (10:30 PM ET). This was not in the 6 PM issue or the ADVZY 182 advisory's terminal-active list, though the advisory does flag SLC under terminal constraints as VCTS (vicinity thunderstorms). No news outlet has picked up the SLC ground stop yet, but flightcheck draws from the FAA NASSTATUS feed and was timestamped to the current minute. SLC is a Delta hub. If you are flying to or from Salt Lake tonight, check your flight status directly.

Las Vegas was spared

The 6 PM issue flagged a possible Las Vegas ground stop around 11 PM ET from L30 TRACON staffing, with the advisory noting "a ground stop may be needed for a 0300Z AAR reduction." That watch is resolved, and the resolution is good news. ADVZY 182 says: "ZLA is confident that they can utilize TBFM instead of a formal initiative at LAS after 00Z. Their expectation is that the delays will not be too large and are easily managed." TBFM (Time-Based Flow Management) meters traffic without a formal ground stop or GDP. Flightcheck shows LAS with 27-minute ground delays classified as "other," consistent with TBFM-managed flow rather than a hard stop. The L30 TRACON staffing trigger remains in the advisory until 0700Z (3 AM ET), so if conditions change overnight the formal initiative could still return, but the FAA's current expectation is no Las Vegas ground stop tonight.

Tracking: the overnight GDPs

Six ground delay programs are running into the overnight hours. Here is where each stands at 9:18 PM ET:

BOS: 1 hour 46 minutes, low ceilings, until 11:59 PM ET. Unchanged from the 6 PM issue. The advisory warns of low cigs as the terminal constraint. The Boston Globe reported 200-plus Logan cancellations and 400-plus delays on Tuesday, with Republic, JetBlue, and Delta the most affected carriers.
DEN: 1 hour 56 minutes, thunderstorms, until 11:59 PM ET. Worsened and extended, as detailed above.
LGA: 43 minutes, weather and surface constraints, until 10:59 PM ET. Newly fired since the 6 PM issue.
SAN: 30 minutes, heavy traffic, until 12:59 AM ET. New since the 6 PM issue. San Diego's chronic volume and construction constraints are the cause, not weather.
SFO: 41 minutes, low visibility and construction, until 2:59 AM ET. Extended at airline request from the 6 PM issue's 6:59 PM end time. Routine overnight program.
CYUL (Montreal): Was running until 8:59 PM ET per the advisory. Expired at delivery time.

Orlando's ground stop expired but departure delays are extreme

The MCO ground stop that the 3 PM issue upgraded to PROBABLE and the 6 PM issue reported as active through 6:30 PM ET has expired. But the residual departure delays are severe: flightcheck shows MCO departure delays of 2 hours 46 minutes to 3 hours due to weather. Tampa has 31-to-45-minute departure delays from thunderstorms, Miami has 31-to-45-minute weather departure delays, and Fort Lauderdale has 15-to-29-minute weather departure delays. The Central Florida and South Florida hotlines and CDRS/SWAP statements run until 0400Z (midnight ET) per the advisory. If you are flying out of Florida tonight, expect significant departure delays even though no terminal ground stop is active.

Staffing and the overnight watch

The advisory's staffing triggers at 9:18 PM ET:

ZDV Area 5: until 0200Z (10 PM ET). Compounding the Denver GDP alongside weather.
F11 TRACON: until 0400Z (midnight ET). Boston-area approach control.
L30 TRACON (Las Vegas): until 0700Z (3 AM ET). Being managed with TBFM, not a formal ground stop, per the advisory.
PHL Area C: was listed until 0100Z (9 PM ET) with "no impacts expected." Expired at delivery time.

The next FAA planning webinar is 0115Z (9:15 PM ET), which just passed. A new advisory may follow in the next hour or two. The SpaceX NROL-95 launch from Cape Canaveral is scheduled for 0637Z to 0804Z (2:37 AM to 4:04 AM ET) tonight, which could affect Florida route structures overnight but is a routine launch operation.

Rebooking

Waivers from earlier today remain active. Delta covers New York (EWR/HPN/JFK/LGA) for travel through July 29 with rebook by August 1, plus Mid-Atlantic (ABE/BOS/BWI/DCA/IAD/PHL) for July 28-29. JetBlue covers ISP/JFK/LGA/EWR/HPN for July 27-29 with rebook by August 1, making today the last day of its waiver window. American and United have had East Coast waivers this week, check their travel-alerts pages directly for current coverage. No new waiver has been posted specifically for tonight's Denver, Salt Lake, or Las Vegas disruptions as of 9:18 PM ET. If your flight is affected by the DEN or SLC programs, call your airline or check their app, as waivers often appear after the FAA's late-morning planning call on the following day.

For real-time status, nasstatus.faa.gov and flightcheck.live remain the best primary sources. The FAA advisory page at fly.faa.gov/adv/adv_spt has the full operations plan text.