Moderate M1.0 solar flare erupts at 12:23 UTC on April 28, 2026

A moderate M1.0 solar flare erupted at 12:23 UTC on April 28, 2026.

Today’s flares include multiple C-class events from active regions 4420 and 4425, such as a C2.3 flare at 01:03 UTC from region 4420, a C2.7 flare at 01:32 UTC from region 4425, 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 X-class or higher M-class events were recorded in the reviewed period.

In 24 hours to 12:30 UTC on April 28, solar activity was at low levels, with the majority of C-class flares produced by regions 4420 and 4425. Slight decay was observed in region 4420, with moderate growth in region 4425, and slight growth in region 4424. No Earth-directed CMEs were detected.

Solar activity is expected to remain at low levels, with a high likelihood of moderate-level flares (R1/R2 – Minor/Moderate) and a chance for X-class (R3/Strong or greater) events through April 30, mainly due to the 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 the greater than 10 MeV proton flux remained 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, and there is a slight chance that proton flux could reach S1 – Minor levels from April 28 to 30.

During the last 24 hours, solar wind parameters were near nominal levels, with wind speeds decreasing from about 450 km/s to 360 km/s. The total magnetic field ranged from 2 to 6 nT, and the Bz component varied between +5 and -3 nT. The solar wind is expected to remain near nominal levels through midday on April 29. Activity is forecast to increase from mid to late April 29 with the arrival of a negative polarity coronal hole high-speed stream, with speeds likely in the 450–550 km/s range and enhanced conditions persisting through April 30.

The geomagnetic field was quiet during the past 24 hours. Mostly quiet conditions are expected for April 28, with unsettled to active levels likely on April 29–30 due to the onset of a negative polarity coronal hole high-speed stream.