Solar activity forecast for the period January 10 - January 16, 2025

Activity level: moderate
X-ray background flux (1.0-8.0 A): in the range C1.0-C7.0 
Radio flux (10.7 cm): a fluctuation in the range 120-230
Events: class C (5-18/day), class M (5-16/period), class X (0-3/period), proton (0-2/period)
Relative sunspot number (Ri): in the range 100-250

Michael Vavra
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic

Geomagnetic activity forecast for the period January 10 - January 16, 2025

Quiet: Jan 10 - 12, 15 - 16
Unsettled: Jan 14 - 16
Active: Jan 13 - 14
Minor storm: unlikely Jan 13 - 14
Major storm:  0
Severe storm: 0

We expect at most quiet conditions within the coming three days.
At the start of new week, an active episode with possible stroming event is possible when the coronal hole 08/-4 reaches the center of solar disk. Nevertheless, the final geomagnetic activity depends on CME frequencies that, currently, cause an intermission.

The last days, we expect quiet to unsettled conditions return.

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 January 10 - January 16, 2025

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – January 9, 2025

For most of the eleven-year solar cycle, two numbers are more or less sufficient to give us a rough estimate of the state of the ionosphere and shortwave propagation conditions: the solar activity index (optimally the solar flux) and the geomagnetic activity index (usually the daily A index or the three-hourly K index is sufficient). We need more information during the high solar activity period and much more at the peak of the high cycle. It may not yet be enough to understand what is going on, let alone predict it. These include the solar wind speed and particle density (free electrons and especially energetic protons) and the strength and polarity of the longitudinal component of the interplanetary magnetic field. Another excellent tool is ionospheric probe measurements, especially ionograms. Unlike the pre-Internet era, we all have access to them.

Yet, or perhaps because of this, we often experience surprises, whether it is a lull or a disturbance. The quiet post-Christmas period and the big solar flares on 30 December were followed by geomagnetic disturbances on 1-2 January, accompanied by auroras and SAR, observable even in the mid-latitudes. The following decrease in solar activity and irregular rises in geomagnetic activity (3-7 January) mostly resulted in a deterioration of shortwave propagation conditions. The improvements were mostly brief and occurred irregularly. Moreover, forecasts of further developments were unreliable.

A further upsurge in solar activity is not expected until the second half of January, after large sunspot groups begin to reappear in the eastern part of solar disk. With few exceptions, major geomagnetic disturbances should follow after the active regions on the Sun reach the central meridian, in February.

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