Moderate M1.5 solar flare erupts at 13:53 UTC on April 28, 2026

A moderate M1.5 solar flare erupted at 13:53 UTC on April 28, 2026.

Today’s flares include several minor C-class events, such as a C2.3 flare peaking at 01:03 UTC from region 4420, a C2.7 flare peaking at 01:32 UTC from region 4425, a C1.6 flare at 05:06 UTC, a C6.0 flare at 08:17 UTC from region 4420, a C9.0 flare at 09:23 UTC from region 4420, a C7.1 flare at 09:32 UTC from region 4420, and a C3.1 flare at 11:18 UTC from region 4420. No M- or X-class flares were confirmed in the available event logs for April 28, 2026.

In 24 hours to 12:30 UTC on April 28, solar activity was at low levels. Most C-class flares were produced by active regions 4420 and 4425. Slight decay was noted in region 4420 while region 4425 saw moderate growth and consolidation. Slight growth was also observed in region 4424. No Earth-directed coronal mass ejections were detected.

Solar activity is expected to remain at low levels but with a high likelihood of reaching moderate levels (R1/R2 – Minor/Moderate radio blackout), and a chance for X-class (R3/Strong or greater) events through April 30, mainly 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. The greater than 10 MeV proton flux remained at background levels. The greater than 2 MeV electron flux is predicted to reach moderate to high levels by April 30 due to coronal hole high-speed stream effects. There is also a slight chance that the greater than 10 MeV proton flux could reach S1 – Minor solar radiation storm thresholds from April 28 to 30 due to the flare potential from regions 4420 and 4425.

Solar wind parameters were near nominal levels over the past 24 hours, with solar wind speed decreasing from approximately 450 km/s to 360 km/s. The total magnetic field ranged from 2 to 6 nT, and the Bz component varied between +5 nT and -3 nT. The phi angle was mostly positive. Solar wind conditions are expected to remain nominal through midday April 29, with an increase in activity expected by mid to late April 29 as a negative polarity coronal hole high-speed stream arrives. Elevated solar wind speeds in the 450–550 km/s range are likely to persist through April 30.

The geomagnetic field was quiet during the past 24 hours. The geomagnetic field is expected to remain mostly quiet on April 28, with unsettled to active levels likely on April 29–30 as a negative polarity coronal hole high-speed stream influences geomagnetic conditions.