official data
SWPC raises a G2 magnetic-storm watch for Sep 9 as CME debris meets a solar wind stream
NOAA Space Weather Prediction Center replaced earlier quiet-leaning guidance with a G2 (Moderate) geomagnetic storm watch for 9 September — tying positive-polarity coronal-hole high-speed stream effects to CMEs that left the Sun 5–6 September — while flares stay in the C-class noise.
Key facts
- Watch
- WATA30 #281 · G2 predicted Sep 9 · G1 Sep 8 · none Sep 10 · supersedes prior watches
- Observed
- ALTK05 #2049 · Kp=5 / G1 reached 2026 Sep 08 1744 UTC
- 3-day peak
- Expected Kp 5.67 (G2) early Sep 9 · CH HSS + CMEs from 05-06 Sep
- Flares
- Latest GOES max C3.4 · not X-class
- Live
- Kp / G-scale → live SWPC HUD — do not freeze this note
Note
Primary: NOAA/NWS SWPC WATA30 Serial 281, 3-Day Forecast issued 2026 Sep 09 0030 UTC, NOAA Scales JSON, and ALTK05 supporting alerts.
What it is not: an X-class flare; an S1+ radiation storm; proof of ECDO, micronova, or pole reversal; inventing live Kp; Lowell.
Why it matters
Distinct from the boarded CME "no big storm" card. Observed G1 on Sep 8. ECDO/micronova remain unlabeled speculation — this is a NOAA G-scale watch only.
Sources
- NOAA/NWS SWPC WATA30 Serial 281
- SWPC 3-Day Forecast
- NOAA Scales JSON
- GOES X-ray flares latest
- NOAA Scales explainer
Official data. Live values go to the HUD / source product.