official data (NOAA / NWS Space Weather Prediction Center 3-Day Forecast, issued 2026 Sep 30 0030 UTC) · ECDO-lane monitor — ECDO remains a labeled hypothesis
SWPC: G1 geomagnetic storm likely Oct 2 from a glancing CME
NOAA’s Space Weather Prediction Center 3-Day Forecast issued 0030 UTC on September 30 says the greatest expected three-hour Kp for Sep 30–Oct 2 is 4.67 — NOAA Scale G1 — with G1 (Minor) geomagnetic storming likely on October 2 from glancing effects of a coronal mass ejection that left the Sun on September 28, after a quiet prior day that topped out at observed Kp 2.
Key facts
- Issued
- 2026 Sep 30 0030 UTC (8:30 PM EDT Sep 29)
- Observed Kp
- Greatest observed 3-hr Kp past 24h: 2 (below NOAA Scale levels)
- Expected Kp
- Greatest expected 3-hr Kp Sep 30–Oct 02: 4.67 (G1). G1 (Minor) likely on 02 Oct due to glancing effects from a CME that left the Sun on 28 Sep
- Oct 2 bins
- 09–12 UT 3.33 · 12–15 UT 3.67 · 15–18 UT 4.67 (G1) · 18–21 UT 4.00 · 21–00 UT 3.33
- Sep 30 / Oct 1
- All bins 1.00–1.67 — below storm levels
- Solar radiation
- Below S-scale past 24h (GOES-19); S1 or greater forecast 1% / 1% / 1% — no S1 or greater expected
- Radio blackouts
- None observed past 24h; R1–R2 10% each day Sep 30–Oct 02; R3+ 1% — slight chance from isolated M-class flares
- Distinct from
- The Sep 24 card was a coronal-hole high-speed-stream G1; this is a glancing-CME G1 for Oct 2
- Scope
- Official SWPC geomagnetic bin on the ECDO lane as monitor only. ECDO remains a labeled hypothesis — this card is not proof of ECDO.
- Live
- Live Kp / G-scale revisions → SWPC HUD / next 3-Day. No invented live Kp dial, aurora claim or CME arrival clock beyond the official G1 likely line.
G1 (Minor) geomagnetic storming is likely on 02 Oct due to glancing effects from a CME that left the Sun on 28 Sep.
NOAA/NWS SWPC 3-Day Forecast, Issued 2026 Sep 30 0030 UTC
Note
NOAA’s Space Weather Prediction Center issued its three-day forecast at 0030 UTC on September 30. The past day stayed quiet — greatest observed three-hour Kp was 2. The outlook is not blank: the product stamps a greatest expected Kp of 4.67, NOAA Scale G1, and says G1 minor geomagnetic storming is likely on October 2 from glancing effects of a coronal mass ejection that left the Sun on September 28. The Kp table puts the G1 flag on the October 2 15–18 UT bin at 4.67, with 4.00 in the following window.
Solar radiation stays off the S-scale in the forecast. Radio blackout odds are listed at 10 percent for R1–R2 and 1 percent for R3 or greater. The September 24 G1 card was a coronal-hole high-speed-stream stamp; this one is a glancing-CME stamp for October 2. Live Kp revisions belong on the SWPC HUD, not this note. ECDO stays a labeled hypothesis only — this card is an official geomagnetic bin.
Why it matters
The observed field stayed quiet at Kp 2. The outlook moved: a glancing CME from September 28 puts a G1 flag on the October 2 15–18 UT bin. A minor-storm forecast from the official product, on the monitor rail — not an X-flare event and not evidence for any broader hypothesis.
Sources
- NOAA / NWS Space Weather Prediction Center
- SWPC homepage
- Earlier Sep 24 coronal-hole G1 card (distinct product)
Primary + secondary attribution as listed. Live values go to the HUD / source product.