Moderate M2.7 solar flare erupts at 22:28 UTC on October 15, 2025

A moderate M2.7 solar flare erupted at 22:28 UTC on October 15, 2025.

Today’s flares include a strong M4.8 event at 04:15 UTC from region 4246, a moderate M3.7 event at 07:18 UTC from region 4246, and an M1.1 flare peaking at 14:10 UTC also from region 4246. multiple C-class flares also took place throughout the day. No X-class flares have been reported.

In 24 hours to 12:30 UTC on October 15, solar activity continued at moderate levels due to several M-class flares. The largest was a long-duration M4.8 event. Most activity was from complex and growing active regions, along with isolated C-class activity from other regions.

Minor to moderate radio blackouts (R1–R2) are likely for the next three days, with a slight chance for an isolated strong (R3) event due to the continued activity in dominant regions.

Active sunspot regions presently observed on the Earth-facing solar disk include AR 4246 (N22W43 – Beta-Gamma-Delta), AR 4248 (N07W13 – Beta-Gamma-Delta), AR 4250 (N07W07 – Beta), AR 4251 (N19E12 – Alpha), AR 4252 (S13E38 – Alpha), and AR 4254 (N10E74 – Alpha).

Over the past 24 hours the greater than 2 MeV electron flux reached high levels, with a maximum flux of 5 130 pfu observed. The greater than 10 MeV proton flux remained at background values. Electron flux is expected to return to nominal to moderate levels on October 15–16. There is a slight chance for a proton event above the S1 – Minor threshold through October 17.

Solar wind parameters were slowly returning to nominal levels, as the effects of a negative polarity coronal hole high-speed stream diminished. Interplanetary magnetic field values stayed at or below 6 nT, with predominantly negative sector orientation, and wind speeds decreased from 700 km/s to 550 km/s. Gradual waning of solar wind parameters is expected to continue as coronal hole effects subside, with disturbed solar wind conditions anticipated later on October 15 through October 17 due to CME arrivals from October 11–13.

Geomagnetic field activity was quiet to unsettled over the past 24 hours. The geomagnetic field is likely to remain unsettled to active until late October 15, when expected CME impacts may increase activity. Moderate storming (G2 – Moderate) is likely on October 16, with minor (G1) storming potentially persisting into October 17.