Solar activity forecast for the period April 16 - April 22, 2021

Activity level: mostly very low (Apr 16, Apr 20-22), mostly very low to low (Apr 17-19) 
X-ray background flux (1.0-8.0 A): in the range A4.0 - A7.0
Radio flux (10.7 cm): a fluctuation in the range 73-78 f.u.
Events: class C (0-2/period), class M (0/period), class X (0/period), proton (0/period)
Relative sunspot number (Ri): in the range 11-55

Bozena Solarova
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic
e-mail: sunwatch(at)asu.cas.cz

Geomagnetic activity forecast for the period April 16 - April 22, 2021

Quiet:  Apr 19 - 21
Unsettled: Apr 18 - 22
Active:  possible Apr 16 - 18, 22
Minor storm: possible Apr 16 - 17
Major storm: 0
Severe storm: 0

Geomagnetic activity summary:
Next week, we expect at most unsettled conditions with two active episodes. The first active episode is expected during the coming days, i.e. Friday, April 16, and Saturday, April 17. The other one is possible at the end of currently forecasted period, i.e. about Thursday, April 22.
Between these expected events, we expect geomagnetic activity decrease to at most unsettled level. About Tuesday, April 22, and Wednesday, April 23, we expect quiet to unsettled conditions. Nevertheless, the second active episode is expected at the end of this week forecast.

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 April 16 - May 11, 2021

Geomagnetic field will be
quiet on: April 25, May 1 - 3, 5
quiet to unsettled on: April 26, 28 - 30, May 6 - 11
quiet to active on: April 19 - 20, 23 - 24
unsettled to active: April 21 - 22, 27
active to disturbed: April 16 - 17, (18,) May 4
 
Solar wind will intensify on: April (16 - 17,) 18 - 19,
(21 - 22, then irregularly between April 23 - May 1,)
May 3 - 5, (6 - 7, 10 - 11)
 
Remarks:
- Parenthesis means lower probability of activity enhancement.
 
F. K. Janda, OK1HH
(from Czech Propagation Interested Group
compiling this geomagnetic activity weekly forecasts since January 1978).
Emails: ok1hh(at)crk.cz, janda(at)planetum.cz
Pmail: OK1HH(at)OK0NAG.#BOH.CZE.EU