Solar activity has been at low levels with mostly weak C-class flares observed from Regions 4172 and 4180.  The largest flare of the period was a C6.8/Sf at 15/1037 UTC from Region 4172.  There are 12 regions on the disk with most being simple in magnetic complexity.  Region 4172 remained the largest region on the disk and continued to decay with its magnetic field decreasing in complexity. All remaining regions were quiet and stable.

No Earth-directed CMEs were observed in available coronagraph imagery. Solar activity is likely to continue at low levels through 17 August.  Despite their decreasing activity, Region 4172 will help maintain a slight chance (35%) for isolated M-class flares (R1-2/Minor-Moderate radio blackouts) in the forecast through 15 August.  Chances decrease to 30% as the region moves beyond the western limb.

Waning influences from the CH HSS will steadily decrease the flux of 2 MeV electrons, but concentrations at geostationary orbit will remain high most likely through 17 August.  Last rotation, electrons remained significantly above the 1,000 pfu threshold for seven day with diurnal maximas above threshold for 11 days.

Solar activity is expected to be at predominately low levels with M-class flare (R1-R2/Minor-Moderate events) activity likely over 11 August to 06 September.

No proton events are expected at geosynchronous orbit, barring significant flare activity.

Geomagnetic field activity is expected to reach active levels on 11 August due to waning positive polarity CH HSS influence.  Periods of minor storming are likely on 18-20 August, with periods of active conditions likely on 22 August, due to negative polarity CH HSS influence.  Active conditions are likely again on 28 August in response to anticipated negative polarity CH HSS influence.  Periods of moderate storming are likely on 05 September, with active levels likely on 04 and 06 September, due to positive polarity CH HSS influence.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for August 14, 2025 by F. K. Janda, OK1HH:

The overall level of solar activity did not change significantly in August.  Medium-size flares were observed almost daily in one or two sunspot groups, while the parameters of the solar wind were most influenced by a coronal hole in the southwestern part of the solar disk.  This clear situation made it possible to correctly predict the positive phase of the geomagnetic disturbance on August 8 (G1), which manifested itself in improved conditions for ionospheric  propagation of short waves.  Particles from the solar flare on August 5 and the intensification of the solar wind from the coronal hole contributed to the disturbance.  This was followed by a negative phase of the disturbance (G2), during which propagation conditions deteriorated significantly.  This was followed by only slightly turbulent development.

The development after August 15 should be calmer, as there are currently no major active areas near the emerging coronal hole in the northeast of the solar disk.

The Predicted Planetary A Index for August 16 to 22 is 5, 5, 15, 25, 15, 8, and 12, with a mean of 12.1.  Predicted Planetary K Index is 2, 2, 5, 5, 5, 3, and 4, with a mean of 3.7.  10.7 centimeter flux is 145, 150, 145, 145, 145, 140, and 145, with a mean of 145.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere . Information and tutorials on propagation can be found at, http://k9la.us/ .

Also, check "Understanding Solar Indices" from September 2002 QST.  https://bit.ly/3Rc8Njt