Weekly forecast

Solar activity forecast for the period February 21 - February 27, 2025

Activity level: low to moderate
X-ray background flux (1.0-8.0 A): in the range B9.8-C5.0
Radio flux (10.7 cm): a fluctuation in the range 100-240
Events: class C (4-15/day), class M (4-17/period), class X (0-1/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 60-200

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

Geomagnetic activity forecast for the period February 21 - February 27, 2025

Quiet: Feb 21 - 25
Unsettled: Feb 24 - 27
Active: Feb 26 - 27
Minor storm: Feb 26 - 27
Major storm:  0
Severe storm: 0

Next days, we expect at most quiet (quiet to unsettled, respectively) conditions till Monday, February 24.

Since February 24, unsettled to active conditions can be expected. An active episode with possible storming event can be expected at the end of currently forecasted period, i.e. February 26 - 27.

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 February 21 - February 27, 2025

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – February 20, 2025

The increase in geomagnetic activity following the decrease in solar activity is a simple phenomenon to explain: systems of magnetic field lines over active regions in the Sun open up and charged particles (both free electrons and the nuclei of hydrogen atoms, or protons themselves) slip through them more easily into space. In Earth's orbit, we see an increase in the solar wind and, consequently, an increase in geomagnetic activity. At the same time, the ionization rate of the ionosphere is increasing, while the shortwave propagation conditions may not only worsen (due to scattering on inhomogeneities) but also improve as the MUF may grow. This was well known, for example, on Saturday 15 February on the Europe-North America route.

The only geomagnetically quiet days in the first half of the month were 3-7 February. Then the solar wind, blowing from the long canyon-shaped coronal hole, intensified and geomagnetic activity was elevated for most of the second third of February. A calm trend can be expected on most days of the last third of the month. Although there does not appear to be a significant increase in solar activity, it is sufficiently high. In addition, spring is approaching, which is good news for the state of the ionosphere.

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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