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Solar activity forecast for the period August 02 - August 08, 2024

Activity level: mostly moderate 
X-ray background flux (1.0-8.0 A): in the range C1.0 - C9.0
Radio flux (10.7 cm): a fluctuation in the range 140-260
Events: class C (3-16/day), class M (5-20/period), class X (0-3/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 90-350

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

Geomagnetic activity forecast for the period August 02 - August 08, 2024

Quiet: Aug 2 - 4, 8
Unsettled: Aug 1, 3, 5 - 7
Active: Aug 1
Minor storm: Aug 1
Major storm: 0
Severe storm: 0


Because of the last CME set, we expect the final active/disturbed event within Thursday, August 1.

Since Friday, August 2, we expect geomagnetic activity decrease to quiet to unsettled level.
It can be interrupted by further active episode probable between August 3 and August 5. The last day, we expect geomagnetic activity decrease to quiet to unsettled level again.

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 August 02 - August 08, 2024

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – August 1, 2024

The largest solar flare so far in the 25th 11-year cycle occurred on July 23 on the far side of the Sun. Fortunately, it was observable by the Solar Orbiter (SolO), a solar probe designed to study the Sun from a heliocentric orbit. The spacecraft was manufactured by Airbus for ESA. The individual measuring instruments and sensors were supplied by ESA Member States, including the Czech Republic, while the US NASA is also involved in the probe. The spacecraft was launched on 10 February 2020 on Atlas V rocket from Cape Canaveral.  Solar Orbiter was in an ideal position to observe the eruption, directly invisible from Earth now. On July 24, SolO was directly hit by particles from the CME, accelerated in a shock front, which increased their energy (a similar ESP event caused the "Great Quebec Blackout" in March 1989, but fortunately only SolO was hit this time).

Over the past seven days, the Sun's rotation has shifted the sunspot active regions from the southeast quadrant of the solar disk to the southwest, or the area where Earth is more likely to be hit by particles ejected from the Sun. Strong eruptive activity has continued. If we just had the Sun overhead, we could register the Dellinger effect, which almost always hit the lower shortwave bands and only rarely the entire shortwave range.

Even a G3 geomagnetic disturbance was predicted, but so far it has been a G2. It could have been worse due to "cannibal CMEs" that made way for other CMEs from subsequent eruptions. Even so, due to "appropriate" timing, there was a significant drop in daily MUF values and an overall worsening of shortwave propagation conditions. The worst days were 26 and 30-31 July. We continue to observe several unstable sunspot regions on the Sun. Therefore, further similar disturbances are very likely.

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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