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Solar activity forecast for the period June 05 - June 11, 2026

Activity level: low to moderate
X-ray background flux (1.0-8.0 A): in the range B6.5-C3.0
Radio flux (10.7 cm): a fluctuation in the range: 106-198
Events: class C (1-8/day), class M (0-3/period), class X (0-1/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 72-197

Karolina Knesplova
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic 

Geomagnetic activity forecast for the period June 05 - June 11, 2026

Quiet:   Jun 7 - 10
Unsettled: Jun 6, 9 - 10
Active:  Jun 4 - 3
Minor storm:   Jun 4 - 5, 11
Major storm:  unlikely Jun 11
Severe storm: 0

Because of concurrent effect of the equatorial coronal hole and the current flare events, we expect the geomagnetic activity enhancement within the coming days.
About Thursday, June4, and Friday, June 5, we expect an active episode with possible storming event.
Another active event with possible geomagnetic storm is also possible at the end of currently forecasted period, i.e. about June 11.
Between this, we expect at most quiet to unsettled conditions.

Tomas Bayer
RWC Prague
Institute of Geophysics of the ASCR, Prague
Department of Geomagnetism
Budkov observatory (BDV)

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere June 05 - June 11, 2026

On May 28, a large sunspot group, AR 4455, began to emerge on the northeastern limb of the solar disk. Its activity had already been monitored in the preceding days by the Solar Orbiter spacecraft, while we were also aware of it thanks to helioseismological observations. In the first days of June, AR 4455 gradually grew, while its configuration pointed to future growth in eruptive activity. A series of moderately energetic eruption eruptions on June 2 turned out to be precursors. The main event, featuring four energetically significant eruptions, took place on June 3, with at least two of them accompanied by a coronal mass ejection (CME), while at least one of which was headed directly toward Earth.

These lines you are currently reading are being written on June 4 at around 16:00 UT, just before more than one particle cloud is expected to hit Earth, marking the start of a geomagnetic disturbance. The disturbance is expected to intensify on June 5 and is likely to continue, albeit with lower intensity, on June 6.

The latest development in solar activity therefore differs significantly from what we witnessed in May, during the previous solar rotation, when solar activity was low and the magnetosphere remained calm in the following days.

Conclusion: Ionospheric propagation conditions during the first weekend of June will be variable and generally poor, with low MUF values. Although a noticeable improvement is expected in the coming days due to increased solar activity, another geomagnetic disturbance can be expected as early as June 10. The only certainty is change!

F. K. Janda, A.R.S. OK1HH
http://ok1hh.nagano.cz/
Emails: ok1hh(at)crk.cz, ok1hh(at)rsys.cz
Pmail: OK1HH(at)OK0NAG.#BOH.CZE.EU

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