Moderate M1.0 solar flare erupts at 15:18 UTC on September 5, 2026

A moderate M1.0 solar flare erupted at 15:18 UTC on September 5, 2026.

Today’s flares include a B6.2 flare from AR 4526 at 03:53 UTC, a C6.4 flare from AR 4524 at 10:45 UTC, and a C1.5 flare from AR 4524 at 12:02 UTC, according to the latest available event data. No M-class or X-class flares are listed other than the M1.0 event at 15:18 UTC on September 5, 2026.

In 24 hours to 12:30 UTC on September 5, solar activity returned to low levels. The largest flares of the period were a C6.7 flare at 19:30 UTC on September 4 and a C6.4 flare at 10:45 UTC on September 5. Associated with the C6.7 flare were Type II and Type IV radio sweeps. Two coronal mass ejections were observed, with modeling suggesting a glancing blow to Earth is possible late on September 7 into early September 8.

Solar activity will likely remain at low levels due to occasional C-class flare activity, with a slight chance for M-class flares (R1 – Minor to R2 – Moderate) through September 7.

Active sunspot regions presently observed on the Earth-facing solar disk include AR 4521 (N09E12 – Alpha), AR 4523 (N10E23 – Alpha), AR 4524 (N12E53 – Beta), AR 4525 (N11E66 – Beta), AR 4526 (S02E69 – Beta), and AR 4527 (N03E71 – Alpha).

Over the past 24 hours, the greater than 2 MeV electron flux reached high levels with a peak of 1 616 pfu. The greater than 10 MeV proton flux remained at background levels. The greater than 2 MeV electron flux is expected to decrease to normal to moderate levels on September 5–7. The greater than 10 MeV proton flux is expected to remain at background levels through September 7.

Solar wind parameters remained at nominal levels over the reporting period. Total field averaged around 6 nT with weak southward Bz deviations to -5 nT. Solar wind speeds decreased from near 400 km/s to below 350 km/s by the end of the period. Phi was predominantly negative with occasional positive swings. Solar wind conditions are expected to remain near background levels until late on September 6, when enhancements are possible due to a solar sector boundary crossing.

Geomagnetic conditions were mostly quiet, with one isolated unsettled period noted. Quiet levels are expected to continue until late on September 6, with isolated unsettled conditions likely thereafter. Unsettled to periodic active conditions are possible on September 7 due to the anticipated effects of the solar sector boundary crossing.