Lightning is a dangerous weather hazard that poses a significant threat to life and property. It can strike at any time, but is most common in the summer months.
For National Lightning Safety Awareness Week (June 22-28, 2025), NOAA is highlighting the capabilities of its Geostationary Lightning Mapper (GLM) instrument onboard the GOES-18 (GOES West) and GOES-19 (GOES East) satellites.
GLM is the first instrument of its kind flown in geostationary orbit. It detects in-cloud, cloud-to-cloud, and cloud-to-ground lightning activity. GLM data also reveals the extent of lightning flashes and the distance they travel. Rapid increases in lightning activity often precede severe and tornadic thunderstorms. Characterizing lightning activity in storms allows forecasters to focus on intensifying storms before they produce damaging winds, hail or tornadoes. GLM data provides awareness of local lightning conditions and promotes better lightning safety decisions.
In large, long-lived storm systems, lightning may travel hundreds of miles before striking the ground. GLM data can show forecasters areas, which may be far from the main line of storms, where the risk of lightning strikes to the ground presents a public safety hazard.
National Weather Service forecasters are also using artificial intelligence (AI) to predict where lightning will strike in the future. This experimental AI model, called LightningCast, predicts where lightning is most likely to occur even before precipitation forms. It also indicates where lightning remains a threat in storms with intermittent lightning activity and helps determine when the threat from lightning is diminishing. The AI tool can accurately predict lightning up to 60 minutes before the first observation of lightning flashes. Clear predictive signals often emerge before rain forms, ahead of weather radar signals. LightningCast was trained using GLM data to recognize complex patterns in GOES satellite imagery that often precede lightning activity. LightningCast is currently in experimental status and is planned to become operational in 2026.
Lightning is particularly hazardous for those working or participating in recreational activities outdoors. Forecasters are using LightningCast to help keep people safe at outdoor concerts, sporting events, and fairs. They also use the data to determine when the lightning threat has passed and it is safe to resume outdoor events.
The advanced capabilities from GOES-18 and GOES-19 allow for new and innovative applications. Not only is the satellite data useful for depicting current weather conditions and aiding in warnings of severe weather, but it is also critical for predicting hazardous conditions in the future. This data is also freely available, providing broad access to lightning information and helping people make more informed safety decisions.