Predikce sluneční a geomagnetické aktivity

Solar activity forecast for the period

May 17 - May 23, 2024

Activity level: moderate to high
X-ray background flux (1.0-8.0 A): in the range C1.0 - C8.0
Radio flux (10.7 cm): a fluctuation in the range 140-250
Events: class C (4-9/day), class M (0-10/period), class X (0-3/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 90-260

Michael Vavra
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic
e-mail: sunwatch(at)


Geomagnetic activity forecast for the period

May 17 - May 23, 2024

Quiet: May 19 - 21
Unsettled: May 18 - 19, 22 - 23
Active: possible May 17 - 18, 23
Minor storm: May 17, 23
Major storm: 0
Severe storm: 0
Geomagnetic activity summary:

Because of the last CME series, we expect active to disturbed conditions next day.
Another active episode probably accompanied by minor storm effect is expectable at the end of currently forecasted period. i.e. about Thursday, May 23.
Between these events, we expect geomagnetic activity decrease to quiet to unsettled level, the quietest intermezzo can be expected between May 19 and 21.

Tomas Bayer, RWC Prague 
Institute of Geophysics of the ASCR, Prague
Department of Geomagnetism
Budkov observatory (BDV)


Geomagnetic activity forecast for the period

May 17 - May 23, 2024

Geomagnetic field will be: 

Quiet on:  
Quiet to unsettled on:  
Quiet to active on:  
Unsettled to active on:  
Active to disturbed:
Solar wind will intensify on:



Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere May 17 - May 23, 2024
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – May 16, 2024

By mid-May, the two huge sunspot groups, AR3663 and AR3664, are already on the far side of the Sun. But the latter is now visible from Mars. The active regions are so large that they can be observed by the Perseverance rover's camera, which is primarily designed to warn of sandstorms. So we've got something to look forward to when it appears on the eastern edge of the solar disk.

But on May 10, both active regions were still visible from Earth, and the activity of AR3664 (which has since merged with AR3668) caused the largest geomagnetic storm in nearly 20 years. The disturbance was in the G5 category, which is an extreme event and thus one of the 20 largest storms in the last 500 years. The fact that the disturbance started after two days of calm, contributed to the appearance of strong, widespread and beautiful auroras, observable even at low latitudes, from where "via aurora" connections could be established within two meters.

The largest known and described disturbance on September 1, 1859 (in Cycle No. 10) is referred to as the "Carrington Event". It was caused by a sunspot group which we call the "Carrington group". AR3664 closely approximated it in size. But this time it didn't produce a CME as large and as well directed towards Earth as it did then. Thank God.

The setting AR3664 still managed to launch the most powerful solar flare of the current solar cycle on May 14 - an X8.7 category eruption from behind the Sun's western limb. But it was actually more than Earth's measured "X8.7" - AR3664 was already beyond the western limb of the solar disk.

High solar activity continues, and Earth has been bombarded by a rain of solar-origin protons in past days as well. Although high solar activity causes the opening of the upper shortwave bands, the high frequency of disturbances and the influx of particles from solar flares result in unstable propagation conditions and frequent occurrence of enhanced attenuation due to the presence of inhomogeneities, not only in the lower layers of the ionosphere.

F. K. Janda, A.R.S. OK1HH
e-mail: ok1hh(at); ok1hh(at)



Informace jsou přebírány z uvedených externích zdrojů a z důvodů přesnosti jsou zveřejňovány výhradně v anglickém jazyce.


Připravované akce

Přednáška "Zpráva o zatmění Slunce 21. srpna"
16. 10. 2017, 19:00 hodin, Zlín




Novinky a aktuality

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Dne 11. února 2022 nás navždy opustil ve věku 73 let náš kamarád a kolega pan František Zloch, dlouholetý aktivní pozorovatel projevů sluneční aktivity na Astronomickém ústavu AV ČR v Ondřejově a popularizátor nejen astronomie.

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