Weekly forecast

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Solar activity forecast for the period March 24 - March 30, 2023

Activity level: low (March 24-26), low to moderate (March 27-30)
X-ray background flux (1.0-8.0 A): in the range B5.5 - B8.5 (March 24-26), in the range B9.5-C2.5 (March 27-30)
Radio flux (10.7 cm): a fluctuation in the range 134-190
Events: class C (2-15/day), class M (0-4/period), class X (0-1/period), proton (0-1/period)
Relative sunspot number (Ri): in the range 60-190

Bozena Solarova
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech Republic

Geomagnetic activity forecast for the period March 24 - March 30, 2023

Quiet: Mar 26, 28 -29
Unsettled: Mar 26 - 28
Active: Mar 24 - 25, 30
Minor storm: Mar 24 - 25
Major storm: 0
Severe storm: 0

Because of coronal hole effect, we expect active conditions with probable minor storming event within coming two days. The active event can be expected just today, March 23. Next two days, we expect geomagnetic activity enhancement continue.
Since Sunday, March 26, we expect geomagnetic activity decrease to unsettled level with likely most quiet interval about Wednesday, March 29.
At the end of currently predicted time, any other active event is possible.

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 March 24 - March 30, 2023

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere – March 23, 2023

If we were to assess solar activity in the last seven days by the number and size of sunspots, or by the number of energetic flares, it would not seem significant. Yet it was, but we only know that because of satellite observations. For example, thanks to NASA's SDO observatory, which recorded a dark plasma eruption at 06:30 UT on 17 March.

The speed of the solar wind began to increase on 21 March. Far more noticeable, however, was a large coronal hole in the southern hemisphere of the Sun near the central meridian. The assumption of a strong solar plasma flow from its bordders pointed to the probable occurrence of a disturbance on March 24.

But the flow was faster. We saw a really strong geomagnetic storm a day earlier, on March 23. During the morning hours, the concentration of free particles around the Earth began to rise rapidly, as a reliable precursor of the coming storm. The geomagnetic disturbance reached K = 7 in the afternoon, so its intensity was rated G3.

Earth's ionosphere responded to the storm with an increase in MUF during 23 March. Since the disturbance should continue, albeit with less intensity, we expect initially below-average shortwave propagation conditions and then a slow return to average.

F. K. Janda, A.R.S. OK1HH
Emails: ok1hh(at)crk.cz, ok1hh(at)rsys.cz

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