On 04 November 2025, the Sun unleashed an X1.8 flare that triggered a brief but strong radio blackout on the daylight side of Earth. Forecasters then flagged a potential impact from a fast, partially Earth-directed coronal mass ejection (CME). By 06 November, the disturbance arrived and the geomagnetic field reached G3 (strong) levels, lighting up high-latitude skies with bright auroras and creating a choppier-than-usual environment for satellites and radio users.
• Flares (≥M): X1.8 peak at 17:34 on 04 Nov from Region 4274 (R3 radio blackout). A strong M7.4 peaked 22:07 on 05 Nov; additional M1.1 at 04:31–04:39 on 06 Nov from Region 4276.
• CMEs: LASCO/CACTus logged multiple CMEs; notably 04 Nov 17:36 a partial-halo (~120°) with median speed ~892 km/s, consistent with the X-flare timing; on 03 Nov ~11:00, several partial-halos with speeds up to ~1000 km/s.
• Solar wind at L1 (DSCOVR): Real-time data showed enhanced conditions during 06 Nov, with speeds around the mid-400 km/s range and southward Bz intervals near −6 nT around ~20:00, sufficient to sustain storming.
• Geomagnetic response: Max Kp = 7 (G3) on 06 Nov; Dst min = −125 nT at 07:00 on 06 Nov—a robust storm. Auroras widely reported at high latitudes during G-level intervals. (NOAA scale reference for G/R/S).
• Active regions & sunspots: Region 4274 (βγδ) dominated, with 4276 producing the 06 Nov M1.1. Daily estimated sunspot number (EISN) rose to 114 on 06 Nov.
• F10.7 cm radio flux: 147 sfu (WWV, 05 Nov); ~159 sfu adjusted at Penticton on 06 Nov. Weekly range ~147–159 sfu.
Conclusion
The events of Solar Week 45 (2025) underline the Sun’s growing intensity as Solar Cycle 25 remains near its peak. The strong G3 storm on 06 November delivered one of the brightest auroral displays of the season and highlighted the importance of continuous monitoring by the space-weather community.
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