Overview
- NOAA confirms an S4 severe solar radiation storm in progress, the strongest since 2003, after ≥10 MeV protons exceeded 10,000 pfu at 18:10 UTC on January 19.
- G4 severe geomagnetic storm conditions were reached following a CME shock, with agencies warning of continued strong geomagnetic activity into early January 20.
- The event stems from a long-duration X1.9 flare on January 18 that launched a full-halo, Earth-directed coronal mass ejection.
- Upstream monitors detected an interplanetary shock at L1 at 19:03 UTC on January 19, signaling magnetospheric compression and prompting sudden-impulse alerts.
- Auroras may extend into mid-latitudes such as Alabama and northern California, while national agencies including New Zealand’s NEMA and Transpower report monitoring with impacts remaining within mitigation limits.