Moderate M4.8 solar flare erupts at 04:15 UTC on October 15, 2025

A moderate M4.8 solar flare erupted at 04:15 UTC on October 15, 2025.

Today’s flares include a radio burst event observed at 00:27 UTC and a radio sweep event beginning at 00:29 UTC and ending at 00:42 UTC, along with an additional radio burst at 00:34 UTC. No X-class or additional M-class solar flares have been reported yet for today from available data.

In 24 hours to 00:30 UTC on October 15, solar activity continued at moderate levels driven by several M-class flares. Active regions 4246 and 4248 produced the majority of this activity, including multiple M2.0 and M3.1 flares, as well as several C-class flares. No new Earth-directed coronal mass ejections were detected during this period.

Minor to moderate (R1 – Minor to R2 – Moderate) radio blackouts are likely for the next three days, with a slight chance for an isolated R3 – Strong event due to ongoing M-class flare activity from active regions 4246 and 4248.

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, greater than 2 MeV electron flux reached high levels, peaking at 5 130 pfu, while greater than 10 MeV proton flux remained background. Electron flux is expected to decrease to nominal to moderate levels on October 15 and 16, with a slight chance for a solar radiation storm at S1 – Minor levels through October 17.

Solar wind parameters were gradually returning to nominal levels as the effect of a negative polarity coronal hole high-speed stream waned. Interplanetary magnetic field strengths stayed at or below 5 nT, and solar wind speeds declined from about 700 km/s to 550 km/s. Gradual waning is expected to continue October 15. Disturbed solar wind conditions are likely late on October 15, with continued disturbances through October 17 due to expected CME impacts from October 11–13 events.

Geomagnetic field activity was quiet to unsettled in the past 24 hours. Unsettled to active geomagnetic conditions are expected until late October 15, with G2 – Moderate geomagnetic storming likely on October 16 as CME effects peak. G1 – Minor storming is likely to persist into October 17.