Weekly forecast

Solar activity forecast for the period October 06 - October 12, 2023

Activity level: mostly low 
X-ray background flux (1.0-8.0 A): in the range B8.0 - C1.2
Radio flux (10.7 cm): a fluctuation in the range 145-165
Events: class C (4-10/day), class M (0-3/period), class X (0/period), proton (0/period)
Relative sunspot number (Ri): in the range 110 - 190

Martina Pavelkova
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic

Geomagnetic activity forecast for the period October 06 - October 12, 2023

Quiet: Oct 6, 9
Unsettled: Oct 7 - 8, 12
Active: Oct 8, 10 - 12
Minor storm: possible Oct 10 - 11
Major storm: 0
Severe storm: 0

After the last active event durung the last night, we expect a short 
geomagnetic activity decrese to Tuesday, October 10. This one, and the 
next days, can bring another active event because of past coronal mass 
ejections and also because of the coronal hole 57/-2. The last days, 
i.e. October 11 - 12, we expect at most unsettled conditions.

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 06 - October 12, 2023

After witnessing a number of solar flares (though at most of moderate
magnitude) during the past month, plus three solar plasma cloud impacts
(CMEs), late September and early October were a bit quieter. However, the
development of solar and especially geomagnetic activity was so irregular
that it was difficult to make predictions for the following days. The
geomagnetic calm on 28 September did not mean an improvement in shortwave
propagation conditions, but rather a deterioration compared to the previous
27 September, which was not calm. The improvement on 2-3 October was the
result of a relative calm with non-declining solar activity.

Subsequent developments were mostly rather quieter. Nevertheless, there
were significant fluctuations in MUF on 4 October with a slight
deterioration. The explanation for the causes can be found mainly in the
timing of the overall development. Specifically, the deteriorations often
occurred after geomagnetic activity increased during the night. In
addition, sporadic layer E activity increased at times (especially on 4-5
October). There was also a slight increase in the concentration of protons
in the solar wind on 3 October and especially still on 5 October.

Irregular propagation conditions can be expected to continue, yet there
should already be less of a difference between expectations and actual
developments in October than there was in September.

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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