Weekly forecast

Solar activity forecast for the period October 04 - October 10, 2024

Activity level: moderate to high
X-ray background flux (1.0-8.0 A): in the range C2.5 - C7.2
Radio flux (10.7 cm): a fluctuation in the range 150-320
Events: class C (3-18/day), class M (5-20/period), class X (0-3/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 130-280

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

Geomagnetic activity forecast for the period October 04 - October 10, 2024

Quiet: Oct 7 - 9
Unsettled: Oct 5 - 8
Active: Oct 4 - 5, 9 - 10
Minor storm: Oct 4 - 5, 10
Major storm: possible Oct 5, 10
Severe storm: 0

Coming two days, we expect geomagnetic activity enhancement due to the last flare emitted from 3842 active region. We expect the CME consequent geomagnetic activity enhancement at the start of coming weekend.
The other active episode is also possible at the end of currently forecasted period, i.e. about Thursday, October 10.

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 October 04 - October 10, 2024

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – October 3, 2024

After AR3811 disappeared from our field of view behind the southwestern limb of the solar disk on September 12, it was continuously tracked by helioseismological methods until September 29, when it reappeared in the southeast, numbered AR3842. Its size and activity on the far side of the Sun suggested that we could look forward to a lot of activity in October.

And so it did. When solar flare X7.1/2b was observed on October 1 with a maximum at 2220 UT, the second largest in the current 11-year cycle, I planned to start with this announcement. But when flare X9.05, newly the largest in X-ray intensity in the same AR3842, was observed on October 3 at 1218 UT, that was no longer the case.

The source region of AR3842 was heading straight towards us. So the plasma cloud was probably heading directly for our ionosphere. Unlike the aforementioned X7.1/2b (which thus moved to the third largest), it is very likely that the CME of October 3 will hit Earth. We therefore expect a disrupted end of the week.

This weekend we can expect low MUF and high LUF on shortwave and QSOs over aurora on VHF. Early next week will see a gradual return to average and then above average radio wave propagation conditions in 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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