Moderate M1.6 solar flare erupts at 09:57 UTC on August 21, 2026

A moderate M1.6 solar flare erupted at 09:57 UTC on August 21, 2026.

Today’s flares include an M1.6 peaking at 09:57 UTC from region 4507. Other events were minor C-class flares from regions 4507 and 4513.

In 24 hours to 00:30 UTC on August 21, solar activity reached moderate levels. The strongest flare of the previous day was an M8.1, with no Earth-directed CME signatures observed. Only minor changes occurred in sunspot regions in the eastern hemisphere.

Solar activity is expected to be at low levels, with a chance for isolated M-class flares (R1-R2/Minor-Moderate) over August 21–23.

Active sunspot regions presently observed on the Earth-facing solar disk include AR 4506 (N12W0 – Beta), AR 4507 (N04W82 – Beta-Gamma), AR 4508 (N09W50 – Alpha), AR 4510 (N12W0 – Beta), AR 4513 (N04E69 – Beta), and AR 4514 (S10W56 – Beta).

Over the past 24 hours, the greater than 2 MeV electron flux at geosynchronous orbit remained at normal to moderate levels. The greater than 10 MeV proton flux remained at background levels. The greater than 2 MeV electron flux is likely to cross the 1 000 pfu threshold on August 21 and remain at high levels on August 22–23 due to coronal hole high speed stream (CH HSS) influences. The greater than 10 MeV proton flux is expected to continue at background levels.

Solar wind parameters continued to reflect waning influence of a negative polarity coronal hole high speed stream. Total magnetic field strength was at or below 6 nT. The Bz component reached as far south as -5 nT. Solar wind speeds gradually declined, with peak speeds near 600 km/s and lows near 500 km/s. Solar wind parameters near Earth are likely to continue reflecting waning influence of a negative polarity coronal hole high speed stream through August 23.

The geomagnetic field was quiet to unsettled. The geomagnetic field is likely to reach active levels over August 20–22 as the ongoing CH HSS influences wane. Unsettled levels are likely on August 23.