Overview
- Forecasters expect G2 (moderate) geomagnetic storming after dark on Dec. 3 into early Dec. 4, with a chance of brief G3 levels if the CME and high‑speed solar wind arrive together.
- The drivers are a Dec. 1 X2 solar flare and a possibly Earth‑directed CME, and a very large sunspot group carries about a 30% chance of another strong flare in the near term.
- Auroras could be visible across northern U.S. states from New York to Idaho and in Alaska, with visibility potentially extending farther south if activity briefly reaches G3.
- NOAA notes that even a glancing CME, combined with already strong and turbulent solar wind, could still yield a G2 storm.
- Bright moonlight and local light pollution may limit faint displays, so observers should seek dark, north‑facing horizons and monitor NOAA’s 30‑minute outlook or aurora‑tracking apps for real‑time updates.