official data (NOAA / NWS Space Weather Prediction Center Forecast Discussion 1230 UTC Sep 30 2026 · SWPC alerts ALTTP2 / ALTTP4 · Solar Region Summary 0030 UTC Sep 30) · ECDO-lane monitor — ECDO remains a labeled hypothesis
SWPC: long-duration C8.6 flare from Region 4535 launches a CME — weak glancing blow possible Oct 4
NOAA’s Space Weather Prediction Center says Region 4535 produced a long-duration C8.6 flare peaking at 0246 UTC on September 30, accompanied by a Type II radio sweep at an estimated 523 km/s, a Type IV burst and a coronal mass ejection first seen in LASCO C2 imagery at 0312 UTC — and that preliminary modeling suggests a weak glancing blow near Earth on October 4, with analysis still ongoing.
Key facts
- Flare (SWPC discussion)
- Long-duration C8.6/1f from Region 4535, peaking 30/0246 UTC — the largest of the period
- Radio (SWPC alerts)
- Type II radio emission began 0252 UTC, estimated velocity 523 km/s · Type IV radio emission began 0256 UTC
- CME
- First observed in LASCO C2 imagery at 30/0312 UTC
- Earth (preliminary)
- “Preliminary modeling of this CME suggests a weak glancing blow near Earth on 04 Oct, but further analysis are ongoing.”
- Region 4535 (SRS 0030 UTC)
- N11W46 at 0000 UTC Sep 30 · Cso · Beta-Gamma magnetic class · area 50 millionths
- Outlook
- Solar activity likely low with a slight chance of an M-flare (R1–R2) through Oct 2 · >2 MeV electron flux high (peak 5,622 pfu Sep 29) · protons at background
- Distinct from
- The boarded G1 (Kp 4.67) watch for Oct 2 is a different CME, from Sep 28; the 1230 UTC 3-Day Forecast keeps it
- Scope
- Official SWPC products on the ECDO-lane monitor. ECDO remains a labeled hypothesis — this card is not proof of ECDO
- Live later
- SWPC model update on the Oct 4 arrival · any watch issuance → SWPC HUD
Preliminary modeling of this CME suggests a weak glancing blow near Earth on 04 Oct, but further analysis are ongoing.
NOAA SWPC Forecast Discussion, issued 2026 Sep 30 1230 UTC
Note
The Sun put a second CME in the queue. NOAA’s Space Weather Prediction Center says Region 4535, a beta-gamma group near N11W46, produced a long-duration C8.6 flare peaking at 0246 UTC on September 30. SWPC alerts logged a Type II radio sweep at an estimated 523 km/s and a Type IV burst minutes later, and a coronal mass ejection appeared in LASCO C2 imagery at 0312 UTC. SWPC’s 1230 UTC discussion says preliminary modeling suggests a weak glancing blow near Earth on October 4, with analysis ongoing.
That is separate from the boarded G1 watch for October 2, which comes from the September 28 CME and stands in the 1230 UTC forecast. Solar activity is expected to stay low with a slight chance of an M-class flare. This card carries SWPC’s published region location, so it pins on the Sun tab. ECDO stays a labeled hypothesis; SWPC model updates go to the HUD.
Why it matters
Two CMEs are now in the queue: the Sep 28 one flagged G1 for Oct 2, and a fresh launch from Region 4535 modeled to brush Earth on Oct 4. Minor on the scale, real on the disk — and it is the first region on the board with a published location, pinned on the Sun tab.
Sources
- NOAA SWPC — Forecast Discussion, issued 2026 Sep 30 1230 UTC
- SWPC Solar Region Summary 273 (Region 4535 N11W46, Beta-Gamma)
- SWPC alerts (Type II 0252 UTC, est. 523 km/s · Type IV 0256 UTC)
- SWPC 3-Day Forecast, 1230 UTC Sep 30 (G1 Oct 2 unchanged)
- Boarded: SWPC G1 likely Oct 2 (separate CME)
Primary + secondary attribution as listed.
More: Space weather
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