Weekly forecast

Solar activity forecast for the period July 18 - July 24, 2025

Activity level: low to moderate
X-ray background flux (1.0-8.0 A): in the range B4.3-C5.5
Radio flux (10.7 cm): a fluctuation in the range 94-183
Events: class C (1-14/day), class M (0-3/period), class X (0-1/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 56-233	

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

Geomagnetic activity forecast for the period July 18 - July 24, 2025

Quiet: Jul 17 - 22
Unsettled: Jul 19,  21- 22
Active: Jul 22 - 24
Minor storm: possible about Jul 23
Major storm:  0
Severe storm: 0

Next days, we expect geomagnetic activity decrease generally. Till Monday, July 21, we expect at most quiet to unsettled conditions.
The geomagnetic activity increase is possible in the interval July 22 - 24, we expect an active episode with possible minor storm effect.

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 July 18 - July 24, 2025

The lowest solar activity during the last solar turnaround (i.e., during the last approximately 27 days) was recorded between July 4 and 8, whereupon it has been increasing since then. The number of sunspot groups has increased from five to eleven. The same applies to the number of solar flares, although most of them were energetically insignificant. So far, developments have been in line with forecasts.

However, geomagnetic activity did not match the assumptions. Although it was significantly increased only on July 13 and 15, the last relatively calm days were July 9-10. After July 14, a calming was expected, but this forecast was pushed further and further forward day by day. Therefore, we did not see the expected improvement in shortwave propagation conditions.

One solar turnaround back (on June 21), activity had already begun to decline, but in previous turns it continued to increase, so it is better not to rely on recurrence, but to give preference to the latest observations. There are six sunspotgroups on the western half of the solar disk and five on the eastern half. Thanks to helioseismological observations, we know of another three to four spots beyond its eastern limb. Therefore solar activity will most likely begin to decline slowly. But above all, the massive coronal hole in the southern half of the solar disk, responsible for a series of solar wind bursts and thus geomagnetic disturbances, will begin to set. Therefore shortwave propagation conditions should slightly improve.

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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