Overview
- NOAA forecasted G2 geomagnetic storms for Dec. 3–4 with a smaller chance of brief G3 periods, estimating roughly a 75% likelihood of minor to moderate storming and about a 25% chance of isolated G3.
- Lancaster University issued a rare red alert on Wednesday for the UK, and the Met Office flagged fast solar wind with a possible CME glance, as confirmed sightings were reported in Suffolk, Norfolk and Oxfordshire.
- In the U.S., up to 22 northern states had a chance to see auroras Wednesday night, and Thursday guidance points to visibility mainly along the northern border, including parts of Idaho, Montana, North Dakota, Minnesota, Wisconsin and Michigan’s Upper Peninsula, plus Alaska.
- Forecasters stress real‑time monitoring because IMF Bz orientation, the timing of solar wind and CME arrivals, cloud cover and moonlight can rapidly change visibility; NOAA’s 30‑minute aurora forecast and popular apps provide timely alerts.
- The current activity follows an X2 solar flare on Dec. 1 with an Earth‑directed CME and a high‑speed stream from a coronal hole during a busy solar period approaching a 2026 peak in auroral opportunities.