Atlanta Hailstorm Grounds Flights, Causes Massive Delays
While Chicago O’Hare recently retook the crown of the country’s busiest airport in terms of number of flights, Atlanta’s Hartsfield-Jackson International Airport (ATL) continues to have the largest number of passengers. A great number of those ATL passengers were significantly inconvenienced on the evening of 6 March 2026 as a hailstorm passed directly over the airport just before 7:00 PM (0000 UTC on the 7th), one of the busiest times of the day for outbound flights. While the hail was not particularly large (no reports made it to the Storm Prediction Center’s Storm Reports for the day) it still forced a ground stop and inspections of dozens of aircraft to ensure that passengers were able to continue safely. Those inspections were hampered by the continued presence of lightning which kept crews indoors for their own safety. It took many hours for planes to be cleared for departure; hundreds of flights were cancelled and the ripples of this are still impacting flight operations the next day.
The atmosphere was somewhat primed for convective activity on this day. A NUCAPS profile near Atlanta from NOAA-20 at 1917 UTC (2:17 PM EST) as plotted by NASA SPoRT’s NUCAPS Savvy site is shown below. Note the presence of steep low-level lapse rates that are contributing to a decent level of surface-based CAPE (1486 J/kg).
The GOES-19 10.3 micron Band 13 view of the event is shown below. The hail event wasn’t the first storm to hit ATL that day, as a previous round of convection had already caused a ground stop earlier. The following loop begins just after the first round moved off to the east and captures the second round from initiation onward. The convection isn’t particularly deep, as can be seen in the relatively warm cloud top temperatures (you can also discern that in the NUCAPS profile above where the tropopause appears to begin around 280 mb or so).
Despite the somewhat low cloud tops, the presence of a vigorous updraft can be discerned with the presence of an enhanced V. We’ve highlighted below in the 2346 UTC frame; just move the slider back and forth to add or remove our subjective annotation.
CIMSS’s ProbSevere Product was also tagging this storm as one to watch, as shown in the following loop (the airport can be found at the right angle in the county boundaries in the center of the image).
Here’s what the ProbSevere metrics for this storm were. There’s an important caveat here: this was not a “severe” hail event, in that hail did not meet or exceed the 1 inch threshold that the National Weather Service has defined for hail to merit the severe designation. There do not appear to be any reports of damage to the planes, which is consistent with this “less than severe” designation. ProbSevere is calibrated to predict the probability of severe events. Therefore, while this 45% probability might seem small for an event that had such a significant impact, it is consistent with what actually took place.
The CIMSS LightningCast product was also monitoring this event. In addition to contour plots overlaid on satellite imagery, LightningCast also provides dashboards at key locations across the United States, including stadiums and airports. Here’s what the LightningCast dashboard for ATL looked like (red) alongside verification from the GOES-19 Geostationary Lightning Mapper. It was clear that lightning was going to hinder ground services.
One challenge with monitoring this event was that it occurred right around sunset, which meant that most of the RGB products used for convection monitoring were not reliable: it was too dark for the daytime products, but there was still too much reflectance in the 3.9 micron band for the nighttime products to be useful. Still, the panoply of other satellite products made it possible to monitor the evolution of this not severe, but still significant, event.