Overview
- An X1.9 flare from Active Region 4341 on Jan. 18 launched a full-halo coronal mass ejection that crossed the Sun–Earth distance in roughly 25 hours.
- NOAA’s Space Weather Prediction Center confirmed an S4 solar radiation storm and severe G4 geomagnetic conditions after the CME’s arrival around 2 p.m. EST on Jan. 19.
- Auroras were seen across large parts of the U.S., the UK and Europe at unusually low latitudes, with Kp readings near 8–9 reported by forecasters.
- NOAA said it notified FEMA, power-grid operators and aviation interests, and coordinated with NASA on astronaut and satellite safety considerations.
- Forecasts indicate geomagnetic and radiation activity should decline after Jan. 20, though elevated effects may continue to affect HF radio, GNSS, satellites and power systems.