07/11/2025

Spaceweather.com reports solar activity was at low levels with only C-class flares observed.ÿ The largest flare during the period was a C8.9 from an unnumbered region beyond the east limb at S13.ÿ This region was also responsible for the majority of the remaining flares alongside Regions 4136 and 4137.

An approximate M2 was observed by Solar Orbiter at 10/1326 UTC just beyond the east limb, brightening can be seen in the SUVI-94 channel at this time.ÿ A slow moving CME was observed in coronagraph imagery, modelled and was determined to not have any impact.

Solar activity is expected to be low with a chance for M-class flares, minor to moderate, through 13 July, primarily due to the flare potential of Region 4136.

Solar wind parameters remained at nominal conditions.ÿ Total field was 2-5 nT with the Bz component between +/-4 nT.ÿ Solar wind speeds were between 350-400 km/s.ÿ The phi angle was variable after 10/0500 UTC.

Nominal solar wind conditions are expected through 11 July.ÿ The co-rotating interacting region associated with a positive polarity CH HSS is expected to arrive 12 July, an enhancement of the solar wind parameters will follow the arrival and remain enhanced thereafter.

Mostly quiet conditions are expected 11 July.ÿ Unsettled to active conditions are likely starting 12 July as Earth moves into a geoeffective position with a positive polarity CH HSS.

There is a decreased chance for minor to moderate radio blackouts on 11 July with most regions on the visible disk rotating off and no appreciable spot groups rotating on.ÿ Conditions could increase on 12 or 13 July as old Regions 4117, 4118, 4120, and 4121 rotate back onto the visible disk.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere July 6 and 10, 2025

Although solar activity is lower this year than it was last year, it is still at the maximum level of the eleven-year cycle.ÿ Moreover, it is quite possible that it will increase further this year.ÿ This is indicated by the continuing slight predominance of activity in the northern half of the solar disk, while in the southern half we more often observe relatively large coronal holes.ÿ The active regions are mostly simple (magnetic type alpha or beta) and therefore, with a few exceptions, do not show significant eruptive activity.

Although solar flares have not been powerful recently, they are quite often accompanied by CMEs.ÿ When ejected particles hit Earth, it is often three to four days after the CME is observed, instead of the usual two to three days. This is one reason why the error in predicting the arrival time of the particle cloud is slightly increasing.ÿ This is especially true when their source is on the far side of the Sun.

The solar wind has finally slowed down in recent days (from speeds of over 800 km/s observed not long ago to less than 400 km/s now) and the interstellar magnetic field has weakened, which has finally had a positive effect on the state of the Earth's ionosphere, as well as the shortwave propagation conditions.ÿ Although the arrival of a high-speed stream from a recurring coronal hole with negative polarity can be expected from July 4, causing unstable geomagnetic conditions, the phenomenon should not last long.ÿ In addition, the low flux of electrons with energies greater than 2 MeV is likely to remain, so a return to fairly favorable conditions can be expected.

In connection with the occurrence of a large coronal hole in the southeastern part of the solar disk, slightly increased geomagnetic activity can be expected.ÿ In the coming days (starting July 13-14), it may reach level G1.

On the above-mentioned days (July 13 to 14, or 1 to 2 days later), the negative impact on the ionosphere could be intensified by declining solar activity. Further developments cannot be predicted with greater accuracy, but the probability of disturbances will be higher in the last third of July.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2] ÿFor an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check this:

https://bit.ly/3Rc8Njt[5]

"Understanding Solar Indices" from September 2002 QST.

The Predicted Planetary A Index for July 12 to 18 is 10, 8, 8, 12, 12, 10, and 10, with a mean of 10.ÿ Predicted Planetary K Index is 4, 3, 3, 4, 4, 4, and 4, with a mean of 3.7.ÿ 10.7 centimeter flux is 105, 105, 110, 115, 120, 125, and 125, with a mean of 115.


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

07/25/2025

Solar activity was at low levels.ÿ The largest flare was a C7.6 from Region 4136.ÿ C-class activity was also observed from several other regions during the highlight period.ÿ No Earth-directed CME activity was observed.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at high levels on 14-20 July in response to persistent positive polarity CH HSS influence.

Geomagnetic field activity reached Minor storm levels on 14, 15, and 17 July due to positive polarity CH HSS influence.ÿ Solar wind speeds were elevated to as high as 700 km/s on 15 and 17 July.ÿ The remaining days were at quiet to active levels despite enhanced solar wind parameters.

Forecast of Solar and Geomagnetic Activity 21 July-16 August 2025

Solar activity is expected to be at mostly low levels with a chance for M-class, Minor to Moderate, flares for the outlook period.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at high levels on 21-22 July, 24-30 July, 5-6 August, and 10-16 August all due to recurrent CH HSS influences.ÿ Low to moderate levels are expected on the remaining days.

Geomagnetic field activity is expected to be at active to Minor storm levels on 23 July, 1-4 August and, 7-14 August due to recurrent CH HSS effects.ÿ Quiet to unsettled levels are expected on the remaining days of the outlook period.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for July 24, 2025 by F. K. Janda, OK1HH:

Less than a year has passed since the probable peak of the 25th eleven-year cycle, which means that we are still in a period of high solar activity.ÿ This does not necessarily mean that there must be a high sunspot number, many eruptions, or a high level of solar radio noise power flux (or solar flux for short).ÿ Currently, there is mainly the high speed of the solar wind that alternately causes high concentrations of negatively charged free electrons in the ionosphere, which quickly recombine with positively charged protons. The result is irregular changes in shortwave propagation conditions, accentuated in the summer by the activity of the sporadic E layer.

From mid-July, sunspot activity initially increased, then declined significantly in the last third of the month as a result of the setting of larger sunspot groups.ÿ No major eruptions were observed in the setting groups. Therefore, the Earth's magnetic field calmed down, especially on July 20-21. The geomagnetic disturbance on July 23 was expected, as the Earth entered the co-rotating interaction region (CIR), where it was hit by solar wind and triggered a G1-class geomagnetic storm (CIRs are transition zones between fast and slow solar wind streams and contain shock waves and amplified magnetic fields similar to those in CMEs).

Forecasts of further developments from various sources now differ considerably. If we look at the part of the far side of the Sun that is currently hidden behind the eastern limb of the solar disk, we can first expect the current level of solar activity and, at the beginning of August, a slight decrease, accompanied by a slight increase in geomagnetic activity.

The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found on YouTube at:ÿ

https://www.youtube.com/watch?v=n1N58cOnedo[1]

The Predicted Planetary A Index for July 26 to August 1 is 5, 5, 5, 5, 5, 5, and 15, with a mean of 6.4.ÿ Predicted Planetary K Index is 2, 2, 2, 2, 2, 2, and 4, with a mean of 2.3.ÿ 10.7 centimeter flux is 135, 135, 130, 130, 130, 130, and 130, with a mean of 131.4.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[3] . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and tutorials on propagation can be found at, http://k9la.us/[5] .

Also, check "Understanding Solar Indices" from September 2002 QST. https://bit.ly/3Rc8Njt[6]


[1] https://www.youtube.com/watch?v=n1N58cOnedo
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

08/01/2025

Spaceweather.com reports solar activity was at low levels with only minor C-class flares observed.ÿ Region 4154 produced a C1.4 flare on 31 July.ÿ Region 4153 contributed the majority of the flares, including a C1.3 flare, a C1.5/Sf flare, and a C1.6 flare on 31 July.ÿ Both of these regions remained mostly unchanged during the period.ÿ Region 4166 exhibited growth during the period yet remained mostly inactive.ÿ Newly numbered Region 4167 exhibited growth during the period and produced a C1.9/Sf flare.ÿ The remaining regions were stable or in decay.

Solar activity is expected to be low with a chance for M-class flares, Minor-Moderate, through 03 August.

Solar wind parameters are expected to continue a waning trend on 01 August as the negative polarity CH HSS moves from its geoeffective location.ÿ An additional disturbance cannot be ruled out for 02 August due to the 30 July CME event mentioned in the previous discussion.ÿ Aside from the possible CME influence, conditions are expected to remain at mostly background levels through 03 August.

Quiet conditions, with isolated unsettled periods, are expected to prevail on 01 August as CH HSS effects gradually wane.ÿ Quiet to unsettled levels are expected on 02 to 03 August, with a slight chance for an isolated active period on 02 August, due to the possible July CME passage.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for July 31, 2025 by F. K. Janda, OK1HH:

We are most likely still in the period of the maximum of 11-year solar activity cycle No. 25.ÿ Its peak was preliminarily recorded in the fall of 2024, but this year's course was very unusual, while its response in the ionosphere was unexpected, especially in May and June.ÿ Solar activity should continue to decline slowly this year, with a more rapid decline expected starting in 2026. Therefore, there is still hope for favorable shortwave propagation conditions this fall, especially in the shorter part of the range (say, at frequencies above 20 MHz).

Last week, only relatively small sunspot groups were observed on the Sun, with no major flares.ÿ This was accompanied by smaller fluctuations in the speed of the solar wind and, therefore, a calmer geomagnetic field.ÿ Although the summer season in the northern hemisphere of the Earth is not favorable for long-distance shortwave propagation, it was still an improvement over previous months.

There should be fewer sunspot groups on the far side of the Sun. But it seems that those that will soon appear will be larger than those we are currently observing.

Solar ultraviolet and X-ray radiation, together with the solar wind, are the main causes of changes in the Earth's ionosphere, but they are not the only ones.ÿ The ionosphere also reacts to processes taking place below it.ÿ These include gravitational waves (formed at the interface between air masses of different densities, for example in meteorological fronts) and infrasound caused by earthquakes and typhoons.ÿ Scientific research into these phenomena is still in its infancy, and although records of changes in the ionosphere following the earthquake on the east coast of Kamchatka (M8.8, Tue 29 July 2025, 23:24:51 UTC) are available, for DX signal hunters this is still more of a curiosity.

The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found on YouTube at:

https://www.youtube.com/watch?v=-XM4kZ-vvRk[1]

The Predicted Planetary A Index for August 2 to 8 is 5, 5, 12, 8, 5, 20, and 15, with a mean of 10.ÿ Predicted Planetary K Index is 2, 2, 4, 3, 2, 5, and 4, with a mean of 3.1.ÿ 10.7 centimeter flux is 140, 150, 155, 155, 155, 155, and 160, with a mean of 152.9.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] ÿand the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[3]. For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and tutorials on propagation can be found at, http://k9la.us/[5] .

Also, check "Understanding Solar Indices" from September 2002 QST. https://bit.ly/3Rc8Njt[6]ÿ


[1] https://www.youtube.com/watch?v=-XM4kZ-vvRk
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

08/08/2025

Solar activity was at low levels on 28 July to 02 August and moderate levels on 03 August.ÿ The largest flare of the period was an M2.9/2b event observed from Region 4168 on 03 August.ÿ The region also produced numerous C-class events. Numerous C-class activity was observed from Regions 4153, 4155, and 4167.ÿ No Earth-directed CME activity was observed.

No proton events were observed at geosynchronous orbit.

Geomagnetic field activity was at quiet to unsettled levels the entire highlight period.ÿ A single active period was observed late on 03 August.ÿ A majority of the unsettled periods was due to weak negative polarity CH HSS influence.ÿ Solar wind speeds were at mostly 400 km/s from 28 July through midday on 30 July and 475-500 km/s from midday 30 July through 03 August with a peak velocity observed at 600 km/s late on 03 August.

Solar activity is expected to be at mostly low levels with a chance for M-class flares for the outlook period.

Geomagnetic field activity is expected to be at active to G1 storm levels on 11 to 15 August, 18 to 22 August and 25 to 30 August due to recurrent CH HSS effects.ÿ Quiet to unsettled levels are expected on the remaining days of the outlook period.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere for August 7, 2025 by F. K. Janda:

Overall solar activity has not changed much in recent days, but it has been higher than on the same days of the previous solar cycle. However, eruption activity increased in the northwestern part of the solar disk.ÿ The M4.4 eruption on May 5, with a maximum at 1553 UTC, was of greatest significance for further development, as it was accompanied by a CME, part of which is heading toward Earth.ÿ It is expected to arrive on August 8, at the same time as a co-rotating interactive region (CIR), should cause an intensification of the solar wind blowing from a large coronal hole in the southern hemisphere of the Sun.

The combination of these two phenomena will cause an increase in geomagnetic activity on August 8.ÿ Thanks to the intensified solar wind, the geomagnetic field will remain active on May 9.ÿ On the first day, there will likely be a positive phase of development, accompanied by an increase in the highest usable frequencies of the F2 ionospheric region, while on the second day, the development will transition to a negative phase, with a decrease in usable frequencies and an overall deterioration in shortwave propagation conditions due to increased attenuation.

After that, rather turbulent developments can be expected until approximately August 12, followed by a calming down from August 13. Overall solar activity should remain only slightly elevated.

The latest report from Dr. Tamitha Skov can be found on YouTube at: https://www.youtube.com/watch?v=SItdIe1X7RU[1]

The Predicted Planetary A Index for August 9 to 15 is 5, 5, 25, 18, 20, 12, and 8, with a mean of 13.2.ÿ Predicted Planetary K Index is 2, 2, 5, 5, 5, 4, and 3, with a mean of 3.7.ÿ 10.7 centimeter flux is 135, 135, 130, 130, 130, 135, and 135, with a mean of 132.9.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[3] . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[4] . Information and tutorials on propagation can be found at, http://k9la.us/[5] .

Also check "Understanding Solar Indices" from September 2002 QST: https://bit.ly/3Rc8Njt[6]


[1] https://www.youtube.com/watch?v=SItdIe1X7RU
[2] http://www.arrl.org/propagation
[3] http://arrl.org/propagation-of-rf-signals
[4] http://arrl.org/the-sun-the-earth-the-ionosphere
[5] http://k9la.us/
[6] https://bit.ly/3Rc8Njt

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

08/15/2025

Solar activity has been at low levels with mostly weak C-class flares observed from Regions 4172 and 4180.ÿ The largest flare of the period was a C6.8/Sf at 15/1037 UTC from Region 4172.ÿ There are 12 regions on the disk with most being simple in magnetic complexity.ÿ 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.ÿ 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.ÿ 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.ÿ 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.ÿ 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.ÿ 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.ÿ 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 ionosphericÿ propagation of short waves.ÿ Particles from the solar flare on August 5 and the intensification of the solar wind from the coronal hole contributed to the disturbance.ÿ This was followed by a negative phase of the disturbance (G2), during which propagation conditions deteriorated significantly.ÿ 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.ÿ Predicted Planetary K Index is 2, 2, 5, 5, 5, 3, and 4, with a mean of 3.7.ÿ 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[1] and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals[2] . For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3] . Information and tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check "Understanding Solar Indices" from September 2002 QST. https://bit.ly/3Rc8Njt[5]


[1] http://www.arrl.org/propagation
[2] http://arrl.org/propagation-of-rf-signals
[3] http://arrl.org/the-sun-the-earth-the-ionosphere
[4] http://k9la.us/
[5] https://bit.ly/3Rc8Njt

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þ Synchronet þ Whiskey Lover's Amateur Radio BBS

08/22/2025

On August 22, Spaceweather.com[1] reports a fast-moving Coronal Mass
Ejection, or CME, left the Sun on August 21.ÿ However, it is not Earth-directed, and is predicted to strike the planet Mars.

Solar activity has decreased back to low levels with a few weak
C-class flares observed from areas located in the northeast quadrant
of the solar disk. There are currently three sunspot regions on the
solar disk with the largest being Region AR4187. This region showed
some weak leader spot growth. The remaining two regions were quiet
and stable.
ÿ
Solar wind parameters reflected negative polarity coronal hole high
speed stream (CH HSS) influences. A disturbed solar wind environment
is likely to continue through August 22.

There is a slight chance for R1 (Minor) radio blackouts through
August 23 due to the anticipated return of old active regions.
Probabilities increase slightly to a chance for an isolated event,
most likely from the east limb, on August 24 as old active regions
return to view.

Active conditions are likely again on August 28 due to negative
polarity Coronal Hole High Speed Stream influences. Periods of G1 to
G2 (Minor-Moderate) storming are likely on September 5, with active
conditions likely on September 4 and 6, due to positive polarity
Coronal Hole High Speed Stream influences. The remainder of the
period is expected to be at quiet or quiet to unsettled levels.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, August 21, 2025, by F. K. Janda, OK1HH:

"Higher solar activity in the first half of August was caused mainly
by two sunspot groups (out of a total of 11-13), whose magnetic
configuration allowed for the occurrence of moderately powerful
eruptions (class M). After their disappearance, the number of groups
dropped to three to five, while only energetically insignificant
eruptions sporadically occurred. Changes in the speed of the solar
wind and the concentration of particles in it had a significant
impact on the Earth's ionosphere. As usual, the source on the Sun
was the boundaries of coronal holes.

"After a brief calm in the geomagnetic field from August 13 to 15,
turbulent developments followed from August 19. At the beginning,
the speed of the solar wind rapidly increased from 350 to 650 km/s,
which was accompanied by a change in the polarity of the
longitudinal component of the interplanetary magnetic field Bz to
positive in a relatively long interval from 1130 to 1630 UT.
Therefore, the deterioration of shortwave propagation conditions was
only slight, while the MUF decline was delayed. We are now likely to
see a series of relatively calm days, probably until August 27.

Major disturbances are not expected to occur until around September
5, when the Earth will enter the same stream of solar particles as
it did around August 9."

The latest video from Dr. Tamitha Skov, WX6SWW, can be found on
YouTube at, https://www.youtube.com/watch?v=brxIxVgiH_A[2] .

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[4]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[5] . Information and
tutorials on propagation can be found at, http://k9la.us/[6] .

Also, check this:

https://bit.ly/3Rc8Njt[7]

"Understanding Solar Indices" from September 2002 QST.

The Predicted Planetary A Index for August 23 to 29 is 5, 5, 8, 8,
10, 12, and 8, with a mean of 8.ÿ Predicted Planetary K Index is 2,
2, 3, 3, 3, 4, and 3, with a mean of 2.9.ÿ 10.7 centimeter flux is
120, 125, 120, 120, 125, 125, and 130, with a mean of 123.6.

ÿ


[1] http://Spaceweather.com
[2] https://www.youtube.com/watch?v=brxIxVgiH_A
[3] http://www.arrl.org/propagation
[4] http://arrl.org/propagation-of-rf-signals
[5] http://arrl.org/the-sun-the-earth-the-ionosphere
[6] http://k9la.us/
[7] https://bit.ly/3Rc8Njt

---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS