Overview
- NOAA’s Space Weather Prediction Center reported an S4 solar radiation storm on January 19, the most intense since October 2003, with ≥10 MeV proton flux exceeding 10,000 pfu at 18:10 UTC.
- An interplanetary shock was detected at L1 at 19:03 UTC on January 19, and G4 geomagnetic storm conditions were confirmed at 2:38 p.m. EST following the CME’s arrival.
- Forecasters warned of operational effects including HF radio blackouts at high latitudes, GPS degradation, satellite anomalies and increased drag, and voltage control problems in power systems at G4 intensity.
- Auroras expanded to unusually low latitudes, with visibility reported or forecast across much of the U.S. and the UK, potentially reaching as far south as Alabama and northern California under favorable conditions.
- The event originated from a long-duration X1.9 flare in Active Region 4341 that produced a full-halo CME, while national operators such as New Zealand’s NEMA and Transpower reported manageable geomagnetically induced currents and no significant local impacts.