Sun news: Sun-stuff bursts could trigger strong auroras

Sun news September 7: Sun-stuff bursts could trigger strong auroras

Today’s top story: A convoy of coronal mass ejections (CMEs) is bearing down on our planet, with the first arrivals expected from later today. Solar observers saw at least four CMEs launch from sunspot region AR4524 over September 5 and 6. These are now racing through interplanetary space and could merge into a combined punch. What might that mean for us? Such a combined structure could drive G1 (minor) to G2 (moderate) geomagnetic storms, with a slight chance of G3 (strong) conditions later this week. In turn, that could bring aurora as far south as New York, London and northern France. The peak of auroral activity is currently looking like Wednesday, but stay tuned as the story unfolds!

Past 24 hours on the sun

(11 UTC September 6 – 11 UTC September 7)

Flare activity: Solar activity stayed at low levels. Observers logged 6 flares: 2 C-class (common) and 4 B-class (weak) events.

• Strongest flare: A C5.0 from AR4524 at 10:31 UTC on September 6. Notably, this C-class flare came with a halo CME, first visible in LASCO C2 imagery at 11:12 UTC. That’s an unusually energetic eruption for such a modest flare classification.
• Lead flare producer: AR4524 dominated, firing 4 of the 6 flares during the period: the C5.0 plus three B-class events.
• For context: An M1.0 flare from decayed AR4520 near the west limb erupted on September 5, just before this reporting period. It came with a fast halo CME and triggered an S1 (minor) proton event.

Sunspot regions: The Earth-facing solar disk displayed approximately 6 numbered sunspot regions. Most appeared quiet and magnetically simple.

• AR4524 (beta-gamma): This region continued to show weak decay. Even so, it remained the most active on the disk. Its beta-gamma configuration sustained C-class flare production, and it produced multiple CMEs over the past two days. It warrants continued monitoring as it rotates toward the disk center.
• AR4528 (alpha): This region received its number during the period. Despite its simple magnetic configuration, it produced a C1.1 flare. Located near the east limb, it will rotate into a more Earth-directed position over the coming days.
• AR4520 (near the west limb): This region had decayed, yet it was the source of the significant M1.0 flare and fast halo CME on September 5. It continues rotating toward the far side.
• The remaining active regions on the disk stayed quiet and stable, producing no significant flaring.

Blasts from the sun? The aftermath of multiple CME eruptions from AR4524 over September 5 and 6 dominated the period. In addition, observers detected a fresh halo CME with the C5.0 flare, adding to an already complex queue of Earth-directed plasma clouds. Multiple CMEs from AR4524 should arrive in a potentially combined structure. The earliest could reach Earth late on September 7, around 20:36 to 23:21 UTC. Additional material should follow through September 8, up to around 18:41 UTC. Confidence in exact timing is low. Still, the combined effect makes G1 to G2 storming likely, with G3 possible if conditions align favorably.

Past 24 hours in space weather

Solar wind: Solar wind speeds remained at nominal background levels through most of the period. The arrival of a slow filament CME from September 2 and the onset of a coronal hole high-speed stream should boost solar wind speeds to elevated levels through September 7.

Bt, Bz and magnetic coupling: The interplanetary magnetic field total strength (Bt) was average. However, a coherent magnetic structure began rotating through the near-Earth environment starting around 20:40 UTC on September 6. Bt climbed by the end of the reporting period. Meanwhile, the Bz component fluctuated with no strongly sustained southward orientation. That limited geomagnetic coupling and kept aurora at bay.

Earth’s magnetic field: Earth’s magnetic field stayed quiet throughout the period, with Kp values remaining in the 0 to 2 range. The lack of sustained southward Bz and the slow solar wind regime kept activity subdued, even though the energetic particle environment stayed slightly elevated after the S1 (minor) proton event on September 5.

What’s ahead? Sun–Earth forecast

Flare activity forecast: Forecasters expect solar activity to remain at low levels, with occasional C-class flares through September 9. A slight chance (20%) exists for M-class (moderate)flares, primarily from AR4524 with its beta-gamma magnetic configuration, and from AR4528 as it rotates further onto the disk. An X-class (strong) flare is very unlikely (1%), given the modest complexity of visible regions.

Geomagnetic activity forecast:

• September 7: Expect unsettled to active conditions (Kp 3-4). A possible glancing CME from September 2 and the onset of the coronal hole high-speed stream should combine to enhance the solar wind environment. Isolated G1 (minor) storm periods are possible. Moreover, the earliest CME arrivals from the September 5 eruptions could reach Earth late in the day, around 20:36 to 23:21 UTC, though timing confidence is low. Aurora may appear over far northern Scotland, Scandinavia and similar latitudes where skies stay clear.
• September 8: Expect unsettled to active conditions, with G1 (minor) storm periods likely as the combined CME arrivals and coronal hole stream influence Earth. The main body of the September 5 and 6 CME cluster should arrive during this day, potentially around 18:41 UTC or earlier. If the CMEs merge effectively, Kp could reach 5 to 6, driving G2 (moderate) storm conditions. Aurora could then appear over Edinburgh, Seattle, Minneapolis, and potentially Toronto, Chicago and northern England.
• September 9: This day carries the greatest chance of significant geomagnetic storm activity. That’s when the full effect of multiple CME arrivals, potentially combined into a single enhanced structure, interacts with Earth’s magnetic field. G1 (minor) to G2 (moderate) storming is likely. A slight chance exists for peak G3 (strong) conditions (Kp 7) if the southward Bz cooperates. Under G3 conditions, aurora could appear as far south as New York, London and northern France. Confidence in timing and magnitude remains low. Even so, the convergence of multiple drivers makes this the day to watch.

The sun in recent days

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Bottom line: Sun news September 7, 2026: A convoy of coronal mass ejections is racing our way. G1-G2 (minor-moderate) storms are likely, with G3 (strong) possible. Auroras may reach New York and London!

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