Overview
- Officials reported G4–G5 geomagnetic conditions overnight January 19–20, with auroras seen across the UK, much of Europe and into the northern and central United States.
- Sightings extended unusually far south, with reports as far as northern Italy in Europe and to Alabama and northern California in the U.S., according to national weather agencies.
- GOES data showed a rare S3 solar radiation storm on January 19 after ≥10 MeV proton flux exceeded 1,000 pfu, increasing risks for high‑latitude aviation and satellites.
- NOAA and the Met Office said the event ranks among the strongest in more than two decades, and they warned of potential impacts to power grids, GNSS, HF radio and spacecraft operations.
- Forecasters expect activity to decline through January 20 with limited aurora chances persisting in northern latitudes, though cloud cover and short‑term solar‑wind conditions will govern visibility.