Solar activity forecast for the period June 06 - June 12, 2025

Activity level: low to moderate
X-ray background flux (1.0-8.0 A): in the range B4.0-C4.0
Radio flux (10.7 cm): a fluctuation in the range 80-170
Events: class C (2-10/day), class M (0-5/period), class X (0-1/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 30-130

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

Geomagnetic activity forecast for the period June 06 - June 12, 2025

Quiet: Jun 6, 8 - 9
Unsettled: Jun 6 - 8, 10 - 12
Active: Jun 7, 10 - 12
Minor storm:  Jun 7, 11 - 12
Major storm:  0
Severe storm: 0

Next two days, we expect the geomagnetic activity at the range of unsettled and active level.
Since Sunday, June 8, we expect partial activity decrease to quiet to unsettled level.
The second half of currently forecasted period, we expected active conditions return with possible minor storm events.

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 06 - June 12, 2025

When assessing solar activity based on the sunspot, or more modernly based on the intensity of solar radio noise, we can tentatively conclude that the maximum of the 25th cycle occurred last spring and summer, or early autumn (the highest smoothed sunspot number was in October 2024: R12 = 160.8, and then declined). Even so, it was much higher than most astronomers had predicted.

But that's not the end of the story. In May of this year in particular, there was a surprising increase in the number and energy of particles in the solar wind, especially during larger solar flares. Particle ionization also affects the Earth's ionosphere, although not as nicely as we would like given the state of the Earth's ionosphere. In short, shortwave propagation conditions were rarely good during May and especially early June 2025. They were mostly unstable, disrupted, with irregular daily cycles and frequent occurrences of increased attenuation.

An exceptional phenomenon is the so-called Forbush effect, also known as the "Forbush decrease" in the intensity of galactic cosmic rays after the arrival of a CME in the vicinity of Earth. The largest decrease in cosmic ray intensity in more than 20 years, by as much as 25%, was recorded on June 1, 2025 (the last time this happened was on October 30, 2003). Particles ejected by the Sun will remain in our vicinity and reduce the intensity of cosmic rays of galactic origin for another week or two.

A decline is generally expected in the further development of solar activity. Only optimists admit that there will be one more increase this year, probably in the northern half of the solar disk.

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