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official data (NOAA / NWS Space Weather Prediction Center WATA20 Serial 1128, issued 2026 Oct 01 1428 UTC) · ECDO-lane monitor — ECDO remains a labeled hypothesis

SWPC watch: minor G1 geomagnetic storm predicted Oct 2 and again Oct 4

Origin Lane: ecdoNOAA SWPC geomagnetic storm watch (global) — impacts mainly poleward of 60° geomagnetic latitudeBy the Doom Signals desk

NOAA’s Space Weather Prediction Center issued a new geomagnetic storm watch at 10:28 AM ET on Thursday: minor, G1-level storming is predicted on October 2, a quieter October 3, and G1 again on October 4. It replaces every watch before it, including the one from September 29 that flagged October 2 alone.

Watch (WATA20 Serial 1128)
Issued 2026 Oct 01 1428 UTC (10:28 AM ET) · Geomagnetic Storm Category G1 Predicted
By day
Oct 02: G1 (Minor) · Oct 03: None (below G1) · Oct 04: G1 (Minor)
Supersedes
“THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT” — including WATA20 Serial 1127 (Sep 29, 1301 UTC), which flagged Oct 02 only (“28 Sep CME inbound”)
Why Oct 2 (Discussion, 1230 UTC)
G1 (Minor) storm levels likely from mid-day Oct 2 due to influences from the 28 Sep CME · 3-Day Forecast: greatest expected Kp 4.67 (G1), in the Oct 2 15–18 UT bin
Why Oct 4
The watch comment is blank — SWPC gives no stated reason in this product. The boarded C8.6 card carries SWPC’s Sep 30 note of a possible weak glancing blow from a Region 4535 CME on Oct 4; that link is not stated in the watch
Oct 3 (Discussion)
Active conditions anticipated as the CME effects wane and a positive-polarity coronal-hole high-speed stream begins
Sun now (Discussion)
Solar activity very low, no C-class or greater flares in the past 24h · no Earth-directed CME observed · Regions 4544 and 4535 decaying
Electrons
Greater-than-2 MeV electron flux continued above 1,000 pfu (ALTEF3 Serial 3750, 1430 UTC Oct 1) · yesterday’s maximum 3,120 pfu at 1435 UTC Sep 30
Potential impacts (G1)
Mainly poleward of 60° geomagnetic latitude · weak power-grid fluctuations can occur · minor impact on satellite operations possible · aurora may be visible at high latitudes, such as northern Michigan and Maine
Scope
Official SWPC watch on the ECDO lane as a monitor only. ECDO remains a labeled hypothesis — this card is not evidence for ECDO.
Live later
Watch upgrades, K-index warnings and alerts → SWPC / HUD

Oct 02: G1 (Minor) · Oct 03: None (Below G1) · Oct 04: G1 (Minor) — THIS SUPERSEDES ANY/ALL PRIOR WATCHES IN EFFECT

NOAA/NWS SWPC, WATA20 Serial 1128, issued 2026 Oct 01 1428 UTC

The Space Weather Prediction Center rewrote its watch on Thursday morning. Serial 1128, issued at 10:28 AM ET, predicts minor G1 geomagnetic storming on October 2, nothing at storm level on October 3, and G1 again on October 4, and it supersedes every watch before it. The September 29 watch it replaces had flagged October 2 alone, from a coronal mass ejection that left the Sun on September 28.

SWPC’s morning discussion still ties October 2 to that CME, with G1 likely from mid-day. It does not explain October 4, and the watch’s comment line is blank. The Sun itself is quiet: no C-class flares in the past day and no Earth-directed CME. A G1 storm means weak grid fluctuations and minor satellite effects, mostly near the poles, and possible aurora in places like northern Michigan and Maine. On this site’s ECDO lane it is a monitor reading, not evidence for the hypothesis.

Why it matters

Two minor storm days in three, on a quiet Sun. G1 is the lowest rung on NOAA’s scale — a flicker for grids and satellites near the poles, and maybe aurora along the northern edge of the U.S. — but it is the official watch, and it now reaches into Sunday, October 4.

Sources

Primary + secondary attribution as listed.

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