Aurora forecast G1-G2 geomagnetic storm

NOAA’s Space Weather Prediction Center said on Sunday, May 17, that G1, or minor, geomagnetic storm conditions were forecast for the day after G2, or moderate, storming was observed in the previous 24 hours. EarthSky reported on May 16 that fast solar wind from a large coronal hole had already pushed geomagnetic activity into G1 and G2 levels overnight. Together, the updates pointed to another night in which aurora visibility could improve across northern parts of North America, especially where skies were dark and clear. NOAA’s public forecast pages said aurora viewing depends on short-term solar-wind conditions and local observing conditions, not the storm scale alone. ### What exactly was forecast for Sunday night? NOAA’s homepage and aurora dashboard both listed G1 minor geomagnetic storm conditions as the forecast for May 17 and again for May 18. Those same NOAA pages showed that the strongest geomagnetic activity observed in the prior 24 hours had reached G2 moderate levels, even though the latest observed level at the time of the snapshot was G0, or no storm. (swpc.noaa.gov) EarthSky said on May 16 that lingering solar-wind effects could keep G1 to G2 storming in play through Sunday night. The site attributed the activity to a fast stream of solar wind flowing from a large coronal hole on the sun. ### What caused the geomagnetic activity this weekend? EarthSky said the weekend disturbance came from fast solar wind rather than from a major coronal mass ejection. (swpc.noaa.gov) Its May 16 update said the solar wind arrived strongly overnight and drove the G1 and G2 storming already observed. NOAA’s advisory outlook for May 11-17 also pointed to a coronal hole as the source. (earthsky.org) The agency said G1 geomagnetic storm levels were likely on May 15-17 because of coronal-hole influence, and it did not forecast other categories of space-weather storms during that outlook period. ### How far south could people expect to see the aurora? NOAA’s aurora-viewing guidance said aurora can be seen from as much as 1,000 kilometers away when it is bright and observing conditions are favorable. (earthsky.org) The agency also said the display is not visible during daylight hours and that its short-term aurora forecast is based on the OVATION model, with a lead time of roughly 30 to 90 minutes. (swpc.noaa.gov) EarthSky said the best chances remained in Canada and the northern United States. Neither NOAA page reviewed here gave a fixed state-by-state visibility line for Sunday; NOAA said in May 2026 that the older “viewline” had been removed from its experimental tonight-and-tomorrow-night product. ### Why did NOAA show G2 observed but only G1 forecast? (swpc.noaa.gov) NOAA’s dashboard separated observed and predicted conditions. The agency showed G2 as the maximum observed level in the previous 24 hours, while listing G1 as the forecast level for May 17 and May 18. That split means forecasters were warning of continued unsettled geomagnetic conditions, but not necessarily a repeat of the strongest burst already recorded. (earthsky.org) NOAA’s pages did not guarantee visible aurora in any specific city, and the agency’s forecast products directed users to live aurora maps for near-term changes. ### Where were the live updates posted? (swpc.noaa.gov) NOAA’s Space Weather Prediction Center maintained the agency’s aurora dashboard, 30-minute aurora forecast and broader forecasts page on Sunday. The alerts, watches and warnings page also carried public bulletins on expected impacts from space weather. Sunday night’s next step was practical rather than procedural: NOAA’s 30-minute aurora forecast page and dashboard were the live products to watch as solar-wind conditions changed on May 17 into early May 18. (swpc.noaa.gov)