Weekly forecast

Solar activity forecast for the period June 20 - June 26, 2025

Activity level: low to moderate
X-ray background flux (1.0-8.0 A): in the range B4.5-C4.0
Radio flux (10.7 cm): a fluctuation in the range 90-175
Events: class C (3-12/day), class M (0-4/period), class X (0-1/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 32-164	

Vlastislav Feik
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic

Geomagnetic activity forecast for the period June 20 - June 26, 2025

Quiet: Jun 21 - 23
Unsettled: Jun 20, 24
Active: Jun 24 - 26
Minor storm:  25 - 26
Major storm:  0
Severe storm: 0

As the coronal hole 59/-3 accompanied by the active region 4117 is currently located at the east ridge of the solar disk, we expect its geoeffectivity in the second half of currently forecasted period.

Friday, June 20, we expect a most unsettled conditions with possible isolated active event. Next days till Tuesday, June 24, we expect at most quiet to unsettled conditions.
Since Tuesday, June 24, we expect geomagnetic activity enhance to active level which can be accompanied by a storming effect about Wednesday, June 25.

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 20 - June 26, 2025

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – June 19, 2025

Solar activity is still at the peak of its eleven-year cycle, even though it reached its maximum last summer (with a monthly average of R = 216 in August last year and a smoothed average of R12 = 160.8 for October last year). The change from last year is the shift of sunspot activity from the southern to the northern half of the solar disc. The appearance of new sunspot activity in the southeast in recent days, close to the solar equator, came as a slight surprise.

This spring, especially in May and early June, we could not fail to notice frequent periods of solar wind intensification and, consequently, a number of geomagnetic disturbances, which caused the critical frequencies of the ionospheric F layer to drop to values corresponding to significantly lower solar activity. In recent days, there has been only a slight improvement.

Most forecasts for future solar activity predict a continuing decline, but if we assume higher activity in the currently setting sunspot groups, we can expect an increase after their appearance on the north-eastern limb of the solar disc in July. Overall, calmer conditions can be expected during the coming summer, although shortwave propagation conditions will continue to be slightly worse than would correspond to the level of solar activity.

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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