Strong M7.7 solar flare erupts at 07:00 UTC on June 3, 2026

A strong M7.7 solar flare erupted at 07:00 UTC on June 3, 2026.

Today’s flares include a major X1.0 at 11:28 UTC, a strong M9.3 at 01:36 UTC, and a strong M7.7 at 07:00 UTC, all from region 4455. Additional moderate and minor events occurred throughout the day, with the most significant flares from region 4455.

In 24 hours to 12:30 UTC on June 3, solar activity reached high levels with two R2 – Moderate solar flares and one R3 – Strong flare. All significant activity originated from a complex, mixed-polarity region. The M9.3 was accompanied by a Type IV radio sweep and a 10.7 cm radio burst peaking at 360 sfu, along with an Earth-directed CME. The M7.7 event produced a 10.7 cm radio burst peaking at 540 sfu and a Type II burst with a shock velocity of 313 km/s, with another Earth-directed CME. The X1.0 produced a 10.7 cm radio burst peaking at 250 sfu. Modeling of CME associations is ongoing. A previous far-sided eruption and filament eruption from June 2 are not expected to be geoeffective.

Solar activity is expected to remain moderate through June 5, with M-class flares likely and a slight chance for X-class events, primarily from regions 4455, 4458, 4461, and 4462.

Active sunspot regions presently observed on the Earth-facing solar disk include AR 4444 (S22W85 – Alpha), AR 4446 (S15W60 – Beta), AR 4452 (N10W0 – Beta), AR 4455 (N13W05 – Beta), AR 4457 (S08W40 – Beta), AR 4458 (S04E07 – Beta), AR 4459 (N14E21 – Beta), AR 4460 (N22W59 – Beta), AR 4461 (S20E72 – Beta), and AR 4462 (N17E75 – Beta).

Over the past 24 hours, the greater than 2 MeV electron flux at geosynchronous orbit was at low to moderate levels, peaking at 684 pfu. The greater than 10 MeV proton flux remained at background levels. The greater than 2 MeV electron flux is expected to persist at low to moderate levels through June 5, with the greater than 10 MeV proton flux forecast to continue at background.

Solar wind parameters remained mildly elevated, with the total magnetic field peaking at 10 nT after a solar sector boundary crossing at 07:55 UTC. Before the crossing, solar wind speed averaged just under 400 km/s, rising to about 425 km/s afterwards. The phi angle remained predominantly negative. Mildly enhanced solar wind conditions may occur on June 3 from the 30 May CME, with more marked enhancements expected late June 3 or early June 4 due to the arrival of a corotating interaction region ahead of a positive polarity coronal hole high-speed stream. Elevated solar wind conditions are anticipated through June 5.

Geomagnetic field conditions were quiet with a period of unsettled activity. Conditions are expected to remain quiet to unsettled on June 3, with a small chance for isolated active periods. On June 4–5, unsettled to active conditions are likely, with occasional periods of G1 – Minor geomagnetic storming possible due to high-speed stream influences and the chance of a transient arrival linked to an earlier M3.3 flare.