Moderate M1.1 solar flare erupts at 14:07 UTC on April 28, 2026

A moderate M1.1 solar flare erupted at 14:07 UTC on April 28, 2026.

Today’s flares include C-class events such as C2.3 at 01:03 UTC from region 4420, C2.7 at 01:32 UTC from region 4425, C1.6 at 05:06 UTC, C6.0 at 08:17 UTC from region 4420, C9.0 at 09:23 UTC from region 4420, C7.1 at 09:32 UTC from region 4420, and C3.1 at 11:18 UTC from region 4420. No M-class or X-class flares other than the reported M1.1 have been documented for April 28, 2026, up to the report creation time.

In 24 hours to 12:30 UTC on April 28, solar activity was at low levels with the majority of the flares being C-class. The most active regions were 4420 and 4425, with region 4420 showing slight intermediate spot decay but retaining a weak delta configuration, region 4425 experiencing moderate growth and consolidation, and region 4424 showing slight growth. No Earth-directed coronal mass ejections were observed.

Solar activity is expected to remain at low levels, with a high likelihood of moderate-level (R1 or R2: Minor/Moderate) solar flares and a chance for X-class (R3: Strong or greater) events through April 30, primarily due to the magnetic complexity of regions 4420 and 4425.

Active sunspot regions presently observed on the Earth-facing solar disk include AR 4420 (N16W29 – Beta-Gamma-Delta), AR 4421 (S12W17 – Alpha), AR 4423 (S05W10 – Beta), AR 4424 (N16E06 – Beta), AR 4425 (N05E36 – Beta-Gamma-Delta), and AR 4427 (S31E40 – Alpha).

Over the past 24 hours, the greater than 2 MeV electron flux at geosynchronous orbit was at low to moderate levels, and greater than 10 MeV proton flux was at background levels. The electron flux is anticipated to reach moderate to high levels on April 30 due to coronal hole high-speed stream influence. There is a slight chance that the proton flux could reach S1 – Minor solar radiation storm levels from April 28 to 30 due to flare potential in active regions.

Over the past 24 hours, solar wind parameters were near nominal levels with wind speed decreasing from approximately 450 km/s to 360 km/s. The interplanetary magnetic field ranged between 2 to 6 nT, and the Bz component varied between +5 and -3 nT. Predominantly positive phi angle was observed. Solar wind parameters are expected to remain at or near nominal levels through midday on April 29. By late April 29, an increase in activity is expected with the onset of a negative polarity coronal hole high-speed stream, likely raising wind speeds to the 450–550 km/s range through April 30.

The geomagnetic field was at quiet levels over the past 24 hours. The geomagnetic field is expected to mostly remain quiet on April 28, with an increase to unsettled to active levels anticipated on April 29–30 as the negative polarity coronal hole high-speed stream arrives.