Increase in solar activity & a stealth CME

Update 2026-03-29, 0330z

Many new sunspot groups in the east with C-class and an M-class flare and coronal mass ejections towards the north-east and south-east. A coronal hole in the northern centre could bring fast solar wind and increased geomagnetic activity.(2026-03-28 0100 UTC)

Synoptics & Forecast – 2026-03-28, 0100z

Active regions

Region 4401 in the north is large and growing, but so far bipolar with closed field lines and inactive, concerning flares and coronal mass ejections.

Region 4403 is a single large sunspot, but recently produced an M3.9 flare and a narrow CME to the northeast. Most recently it erupted again with a C-class flare, dimming and coronal wave.

Regions 4404 and 4406 appear relatively simple at first, but they could develop further. There may be further regions behind the eastern limb.

Region 4405 was very active with C-class flares and CMEs. It was formed on the far side and is therefore still relatively young. Its proximity to the coronal hole could lead to a further increase in activity.

Coronal holes

The positively polarised coronal hole CH34+ lies north of the equator and even further north of the Earth-Sun axis. Its fast solar wind will therefore not be very strong, the stream interaction region could arrive late on 28 or 29 March and cause increased geomagnetic activity.

In about a week, the fast solar wind from the coronal hole CH36- could cause increased geomagnetic activity.

Stealth CME

In the north-west we see an enlargement of the area of CH34+ in SDO AIA 211 – coronal material was evacuated into space. Initially very slowly, then accelerated by the fast solar wind of the coronal hole.

We see the main direction to the north-west and only a slight scratching of the ecliptic. The CME can be recognised relatively clearly in the coronograph, so it is not quite a typical stealth CME, but there are only traces on the surface of the sun as rather inconspicuous dimming and brightening, as the material comes from the high corona and slowly leaves the sun without a flare.

Perhaps parts of the CME will reach us with the arrival of the stream interaction region (fast solar wind meets slow solar wind and compresses the magnetic field) at the weekend (28 March, more likely 29 March). Met Office sees a chance of G1 MINOR STORM.

Old and new magnetic poles of the sun

CH34+ can be seen as the remnant of the northern polar coronal hole of solar cycle 25, CH36- as the southern one. CH35+ in the south pole already represents the new southern coronal hole of the next solar cycle 26 (the new south pole) now with positive polarity. The new northern polar coronal hole is not yet stable, it keeps opening and closing in different places.

Perhaps (probably) the increase in activity in the east of the Sun is due to the constellation of coronal holes and the meeting of the current solar cycle 25 with the new No. 26.

Also striking are the bands running from north-east to south-west, starting in the northern hemisphere and ending in the southern hemisphere – a possible sign of “planetary” Rossby waves? What is a little strange about this is that we would normally expect symmetrical structures >>> and not such ///. Perhaps it is just an optical illusion.

2026-03-28, 0500z – Region 4055: M1.3 flare and complex eruption

Complex eruption with a moderate, long-duration M1.3 flare from Region 4405 in the south-east of the Sun.

Significant dimming to the north, opening field lines, post-eruptive arcades and radio emissions indicate the release of a CME. Earth-directed components are rather unlikely.

2026-03-29, 0330z – Solar Synoptic Map

Now including CME labels (provided a CME has previously occurred in the region – the best predictor of a further CME) and maximum solar flare intensity per region; SWPC/MOSWOC flare probabilities from M 10%; number of sunspots, Carrington longitudes for each region, yesterday’s F10.7, current SILSO sunspot number

Next post:
X1.4 Flare and CME (’solar storm‘) with earth-directed components

More updates always on X or bluesky

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