Solar Activity Increases: M-Class Flare Erupts, Auroras Possible

Solar activity has increased after a quiet period. The main event was a moderate M1.3-class solar flare. It erupted from a sunspot region called AR4405 at 2:13 UTC on March 28, 2026. This was the strongest flare in the past day. It was stronger than the many smaller C-class flares from the day before. The flare caused a minor radio blackout. This briefly disrupted high-frequency radio communications over Malaysia.

The sunspot region AR4405 was the most active area. It is a large region on the southeastern edge of the sun. It produced seven of the eight flares recorded in the past day. Another region, AR4401, is also being watched. It is located near the center of the sun's Earth-facing side and has a more complex magnetic structure. Forecasters were monitoring it closely as it changed.

Overall space weather conditions were calm at the time. Solar wind speeds dropped back to normal background levels. Earth's magnetic field was quiet. However, forecasters thought this calm might not last. A fast stream of solar wind from a coronal hole was expected to arrive by late March 29. This could increase geomagnetic activity. It also gave people who watch for auroras a reason to hope for possible displays as the new week began.

Flare Activity: Solar activity was at moderate levels. The sun produced 8 flares in total: 1 M-class flare and 7 C-class flares.

The strongest was the M1.3 flare from region AR4405. This region was the main producer, responsible for 6 of the 8 flares. Its activity included the M1.3 event and five C-class flares. One earlier C5.4 flare from this region was notable. It was a very long-duration event that released energy similar to an M-class flare.

Sunspot Regions: Nine numbered active regions were on the Earth-facing side of the sun. One region rotated out of view.

Coronal Mass Ejections (CMEs): Forecasters saw several CME events, but none were headed toward Earth.

Solar Wind: Conditions returned to a normal, ambient state. This followed the decline of a previous fast solar wind stream. Wind speeds were highest early in the period and then gradually dropped. The strength of the interplanetary magnetic field (IMF) reached moderate levels before settling lower. The Bz component, which is important for geomagnetic activity, shifted between north and south. Overall, conditions were like the slow solar wind.

Earth's Magnetic Field: The geomagnetic field was quiet. The planetary K-index (Kp), which measures disturbance, was low. Conditions did not reach storm levels. Aurora activity was only at background levels in the usual auroral zones over northern Canada, Alaska, Iceland, and northern Scandinavia.

Flare Forecast: Solar activity was expected to stay at very low to low levels. For March 28, 2026, forecasters assessed a 45% chance for an M-class (moderate) flare and a 5% chance for an X-class (strong) flare.

Geomagnetic Activity Forecast:

• March 28, 2026: Quiet conditions were forecast to continue. Solar wind speeds were expected to stay near background levels. The Kp index was likely to be 0–2. Auroras were forecast to stay in the high-latitude zones.
• March 29, 2026: A change was expected. Conditions were forecast to be near background for most of the day. By late March 29, a fast solar wind stream from a coronal hole was projected to start arriving. This stream might have mixed with weak effects from two older coronal mass ejections. Together, they could have pushed conditions to unsettled or active levels (Kp 3–5). There was a chance of reaching G1 (minor) geomagnetic storm levels. If a G1 storm happened, auroras might have been seen from places like Seattle, Edinburgh, and southern Scandinavia if the sky was clear.
• March 30, 2026: Unsettled-to-active conditions were forecast to continue because of the coronal hole stream. The best chance for G1 storm conditions was projected for this day. The Kp index was expected to be 3–5. This would have provided good opportunities for auroral displays in the far north of Scotland, northern Scandinavia, Alaska, and northern Canada on the nights of March 29–30 and March 30–31.
• March 31, 2026: The influence of the fast solar wind stream was projected to weaken. Conditions were forecast to gradually return to quiet-to-unsettled levels (Kp 2–3).

March 27, 2026: Solar activity was low, dominated by C-class flares. A new, unnumbered region on the sun's southeastern edge produced most flares.

March 26, 2026: Solar activity rose to moderate-high levels. A newly rotated region, labeled AR4403, produced a powerful M3.9 flare. This triggered a minor radio blackout over the Indian Ocean.

March 25, 2026: A significant eruption from behind the sun's northeastern edge hinted at an active region that would soon rotate into Earth's view.

March 24-23, 2026: A geomagnetic storm from the previous weekend began to fade. However, auroras had been visible at mid-latitudes, such as New York and London. This was due to a combination of coronal mass ejections and a fast solar wind stream, which caused a G3 (strong) geomagnetic storm.

Bottom line: The main solar news for March 28, 2026, was an M1.3 flare from region AR4405. Forecasters were watching for increased geomagnetic activity and possible auroras as a fast solar wind stream was expected to arrive around March 29.