07/06/2026

A series of M-class flares - all from Region 4479 - pushed solar activity to high levels this week. The largest of the flares was an M3.5 on July 1.
�
An earlier flare from this region, M1.3 accompanied by a 1N H-alpha flare which peaked late July 1, appears to have been associated with dimming and a coronal mass ejection (CME) first identified in CCOR-1 imagery. Initial analysis suggests the CME has an Earth-directed component, although the speed derived from the available imagery was only 300-450 km/s. Further analysis is needed to increase confidence.
�
Flux emergence and some consolidation around the leader and trailer spots was observed in Region 4479 during the period. Region 4478 produced an M8.5/2b flare on July 1 following occasional C-class flaring. This region also exhibited flux emergence in the intermediate spots and around the leader spot. Finally, Region 4480 was quiescent although some intermediate spots developed.
�
Solar activity is likely to decrease to moderate levels (R1-R2, minor-moderate) with a slight chance for X-class flares (R3-strong), particularly from Region 4479.
�
Solar wind parameters were enhanced with CME passage. Solar wind speeds have ranged from approximately 360 - 425 km/s. The CME from June 30 is expected to arrive early on July 3, bringing disturbed solar wind conditions that are expected to last into July 4. There is enough uncertainty around the CME timing that an arrival mid-to-late on July 2 is possible.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 2, 2026, by F. K. Janda, OK1HH:

Near the extensive active region AR4478, which the Solar Orbiter had been observing for several days before it rose on the southeastern limb of the solar disk, a small region, AR4479, was initially discovered. Both regions grew rapidly in the following days, while the configuration of their magnetic fields indicated nearby increased eruptive activity. High-energy flares occurred primarily on and after June 30, while some were accompanied by CMEs.

Because the CMEs occurred near the solar central meridian, Earth was strongly affected by an intensified solar wind. Shortwave propagation conditions were favorable during the so-called positive phase of the disturbance on June 30, but very unfavorable during the negative phase on July 1. A similar pattern may recur in the coming days!

The predicted Planetary A Index for July 7 to July 12 is 14, 5, 5, 12, 15, 12, and 8, with a mean of 10.1. The predicted Planetary K Index is 4, 2, 2, 4, 4, 4, and 3, with a mean of 3.3. Predicted 10.7 centimeter flux is 130, 125, 125, 125, 120, 125, and 120, with a mean of 124.3.

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 this:

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

"Understanding Solar Indices" from September 2002�QST.


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

07/10/2026

Solar activity reached moderate levels with an M1.5/1N flare on July 8 from Region 4482.

There are currently five numbered regions on the visible disk. Region 4482 demonstrated continued growth and developed a delta spot within its trailing spot group. Region 4485 displayed new flux emergence. Regions 4486 and 4487 were newly numbered during the period. Region 4481 was stable and remained an unremarkable unipolar group.

No Earth-directed CMEs were observed in available coronagraph imagery.

Solar activity is expected to remain at low levels through July 11, with a high chance for M-class (R1-R2/minor-moderate) flares and a slight chance for X-class (R3/strong and greater) events. This flare probability is almost entirely due to the complexity and potential of Region 4482.

Solar wind parameters reflected near ambient background conditions. Solar wind speeds were generally near 400 km/s. The phi angle was predominantly in the positive sector.

Enhancements are anticipated to begin on July 9 and continue through July 11 with the arrival of a co-rotating interaction region (CIR) ahead of a negative polarity coronal hole high-speed stream (-CH HSS).

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 9, 2026, by F. K. Janda, OK1HH:

The power flux of solar radio noise at a frequency of 2800 MHz (at a wavelength of 10.7 cm), which is measured precisely every day at noon local time in Penticton, Canada, and is referred to as the "solar flux," remains at a relatively low level. The reason is that the number of observed sunspot groups on the solar disk dropped to just three on July 7, the lowest number recorded during a single solar rotation (the following day, their number increased to five). The largest active region, NOAA 4482, which we observe in the southeast of the solar disk, has not changed significantly in size and continues to produce moderate-intensity flares on a regular basis. All three coronal holes are currently relatively far from it. The intensity of the solar wind is changing only slightly; periods of increased geomagnetic activity alternate with quiet days, making it impossible to accurately predict future developments.

A more pronounced increase in solar activity is expected in the second half of July (with a gradual increase in solar flux up to 180 s.f.u.). More significant geomagnetic activity can be expected if major solar flares occur, especially if they occur near or west of the central meridian. This is likely to happen sometime in the second half of July.

The predicted Planetary A Index for July 11 to 17 is 12, 8, 5, 5, 5, 10, and 8, with a mean of 7.6. The predicted Planetary K Index is 4, 3, 2, 2, 2, 3, and 3, with a mean of 2.7. Predicted 10.7 centimeter flux is 125, 120, 125, 130, 135, 135, and 135, with a mean of 129.3.

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 this:

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

"Understanding Solar Indices" from September 2002�QST.


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

07/20/2026

Solar activity has remained at low levels, with an occasional
low-level C-class flaring observed, including a C3.3/Sf flare on July
15 from Region 4489. The largest event of the period, a long-duration
C8.9 flare that peaked on July 15, originated from a returning region
on the eastern limb. This region is not yet numbered and will be
assessed once it has become visible from Earth's perspective, but the
latest imagery from Solar Orbiter suggested only a simple and rather
average bipolar group with a relatively small penumbra.
�
There are two numbered sunspot regions on the visible disk. Region
4482 showed minor new flux emergence behind its mature primary spot,
developing a bipolar configuration. As Region 4489 rotated further
into view and limb foreshortening effects decreased, very small opposite-polarity trailing spots became visible, making it a stable
bipolar group. Additionally, a small, magnetically simple, region
tracked in Solar Orbiter imagery has begun to rotate over the east
limb near S10. No Earth-directed CMEs were observed in available
coronagraph imagery.
�
Solar activity is expected to remain at low levels through July 18,
with a slight chance for M-class (R1-R2/minor-moderate) flares,
primarily driven by active regions anticipated to rotate onto the
visible disk over the next few days.
�
Solar wind parameters reflected possible combined glancing coronal
mass ejection (CME) effects and subsequent weak positive polarity
coronal hole high-speed stream (+CH HSS) influences.
�
A return to more ambient-like conditions is expected over the next
three days.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere,� July 16, 2026, by F. K. Janda, OK1HH:

The significant decline in solar activity throughout the first half
of July is clearly illustrated by the solar flux values, which fell
from 203 s.f.u. (July 2) to 100 s.f.u. (July 14-15), as well as by
the number of sunspot groups, which dropped from five to two. A
significant drop in the critical frequencies of the F2 layer began as
early as July 4 during the geomagnetic disturbance of July 4-5, and
due to the sharp decline in solar activity, these values returned to
average levels only very slowly in the following days. Consequently,
the sporadic E layer had an even greater impact on shortwave
propagation (particularly in the mid-latitudes of Europe on July
14-16).

The increase in solar activity, which is expected to begin as early
as the end of this week, while should last nearly until the end of
the month, will result in significantly better shortwave propagation
conditions than those experienced in the first half of the month.
More significant changes (possibly an initial rise, but then very
likely a temporary drop in MUF) will likely be caused by a
geomagnetic disturbance, which is tentatively expected on July 21-22.

The predicted Planetary A Index for July 18 to 24 is 5, 5, 5, 5, 12,
10, and 7, with a mean of 7.0. The predicted Planetary K Index is 2,
2, 2, 2, 4, 3, and 2, with a mean of 2.4. Predicted 10.7 centimeter
flux is 135, 135, 135, 135, 135, 135, and 135, with a mean of 135.0.

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 this:

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

"Understanding Solar Indices" from September 2002�QST.


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

07/24/2026

Solar activity continued at moderate levels as Region 4493 produced an M3.6 flare on July 22, which was the largest event of the period and was associated with a 10.7-centimeter radio burst of 200 solar flux units (sfu). Additionally, 4493 produced a C3.4 flare on July 22, which was associated with another 10.7-cm radio burst of 150 sfu.
�
Region 4493 continued to undergo consolidation in its leading and trailing spots, but showed signs of new flux emergence in its intermediate area during the early hours of the reporting period. Region 4494 developed new, simple spots, but remained uni-polar. The remaining two numbered active regions were relatively stable and quiet.
�
A filament eruption NW of Region 4493 on July 21 was modeled and assessed to be at least partially Earth-directed. While modeling efforts suggest that a bulk of the material should pass north and ahead of Earth s orbit, this is low confidence given the faintness of this event in Sun-Earth line-focused coronagraph imagery and compounded by likely interaction with the coronal hole in the vicinity of the source location.
�
Additional M-class flare activity (R1-R2 radio blackouts) is likely through July 25 primarily due to the flare potential currently exhibited by AR 4493.
�
Solar wind parameters were mildly enhanced under a sustained negative polarity coronal hole high-speed stream (CH HSS) regime and a possible secondary Co-rotating Interaction Region (CIR). Solar wind speeds were roughly between 400 and 482 km/s.
�
The current regime is expected to largely continue through July 25. Additional enhancements are possible beginning late on July 23 due to a coronal mass ejection (CME) that left the sun on July 20, with stronger enhancements arriving by early on July 24 with the arrival of the aforementioned CME event from July 21.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 23, 2026, by F. K. Janda, OK1HH:

A relatively large sunspot group, which was already very conspicuous in images from the SOLAR ORBITER spacecraft, was designated NOAA 4493 after its discovery as an active region on the northeastern limb of the solar disk. It produced class C and M flares on a daily basis. It is currently located in the northwest of the solar disk. As it grew, it disrupted a long north-south coronal hole and remains the largest and most complex sunspot group on the visible disk, accounting for most of the observed eruptive activity. The eruption observed within it on July 20 was accompanied by a CME. The ejected particles triggered a geomagnetic disturbance on the afternoon of July 23.

As a result of this activity, the ionosphere is currently undergoing variable conditions, characterized albeit irregularly by a pronounced presence of the summer sporadic E layer in the Earth s northern hemisphere. In the coming days, geomagnetic activity should begin to gradually decline (no earlier than July 25). Increased solar activity will likely persist almost until the end of the month. Conditions for ionospheric radio propagation will therefore remain variable, with irregular occurrences of relatively very favorable days.

The predicted Planetary A Index for July 25 to 31 is 5, 5, 5, 5, 5, 5, and 5, with a mean of 5.0. The predicted Planetary K Index is 2, 2, 2, 2, 2, 2, and 2, with a mean of 2.0. The predicted 10.7 centimeter flux is 125, 125, 120, 118, 118, 115, and 112, with a mean of 119.0.

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 this:

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

"Understanding Solar Indices" from September 2002�QST


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

08/01/2026

Solar activity has remained at low levels. Region 4494 exhibited decay in its trailing spots as its flare activity subsided. Region 4498 rotated into better viewing positioning, revealing mixed polarity just behind its large leading spot, and was responsible for a handful of low-level C-class flares.

Region 4499 underwent evolution, gaining additional spots and producing a low-level C-class flare. Region 4501 rapidly emerged this period, developed rudimentary penumbra on its leading and trailing spots, produced a low-level C-class flare and was thus subsequently numbered. The remaining numbered active regions were unremarkable in relation.

No Earth-directed CMEs were observed in available coronagraph imagery.

Solar activity is expected to be low with a chance for M-class flares (R1-R2, minor-moderate) through August 1.

Solar wind parameters were at nominal levels. Solar wind speeds roughly ranged from 310 km/s to 401 km/s. A disturbed solar wind environment will likely return July 30 due to the prospect of combined positive polarity coronal high speed stream (CH HSS) effects and coronal mass ejection (CME) arrivals from events that left the Sun on July 26 - 27. An additional disturbance is likely on August 1 with the arrival of an additional CME that left the Sun late on July 27.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 30, 2026, by F. K. Janda, OK1HH:

During the last third of July, solar activity initially rose, while remained at a higher level until the end of the month. Although solar flares occasionally reached moderate intensity, while were exceptionally accompanied by coronal mass ejections, the Earth was not affected by them (though this could still happen by the end of July or early August, partly because there is a coronal hole in the southwestern part of the disk). There is only one active region on the far side of the Sun. Therefore, as the nine regions currently being observed fade, overall activity will decline shortly after the beginning of August.

Shorter periods of increased geomagnetic activity may still occur in late July and at the beginning and end of the first third of August. Following the expected decline in solar activity, these will be followed at irregular intervals by shorter periods of deteriorated ionospheric conditions for shortwave propagation.

The predicted Planetary A Index for July 31 to August 6 is 8, 5, 5, 5, 12, 15, and 10, with a mean of 8.6. The predicted Planetary K Index is 3, 2, 2, 2, 4, 3, and 3, with a mean of 2.7. Predicted 10.7 centimeter flux is 135, 130, 125, 125, 125, 120, and 125, with a mean of 126.4.

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 this:

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

"Understanding Solar Indices" from September 2002�QST


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

08/07/2026

Solar activity has been at low levels, with occasional B-class flaring and isolated low-level C-class flares observed. The largest event of the period was a C1.6/Sf flare on August 5 from Region 4502.
�
The six numbered sunspot regions on the visible disk are mostly stable or in varying stages of decay. Region 4498 showed a slight decrease in penumbral extent. Region 4499 declined in length and area, though limb foreshortening hindered complete characterization of its magnetic structure. Region 4500 weakened in its leading spot. Region 4501 lost its trailing spots, decaying into a unipolar group.
�
Region 4502 exhibited consolidation across both magnetic poles. Region 4503 was limited by foreshortening near the southeast limb, but appeared to show modest new flux emergence in its trailing spots to become a bipolar group.
�
No Earth-directed coronal mass ejections (CMEs) were observed in available coronagraph imagery.
�
With ongoing region decay and several active regions in the western hemisphere expected to rotate off the disk over the coming days, there is a decreasing chance for M-class (R1-R2/minor-moderate) flares August 6. Current Solar Orbiter Helioseismic and Magnetic Imager (HMI) imagery suggests no significant returning regions during the forecast period.
�
Solar wind parameters remained at quiet, ambient, levels throughout the period. Solar wind speeds reflected a slow wind regime, gradually declining from early values near 400 km/s down to approximately 345 km/s late in the period. The phi angle remained predominantly in the positive (away from the Sun) sector.
�
Solar wind parameters are expected to remain in a slow wind regime through early August 7. Later in the day, enhancements are anticipated to begin due to the arrival of CMEs that departed the Sun on August 3. These CME enhancements may persist into August 8, alongside potential weak influences from a negative polarity coronal hole high-speed stream (-CH HSS) that is likely too far south to become significantly geoeffective.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, August 6, 2026, by F. K. Janda, OK1HH:

The effects of the expected decline in solar activity (within the context of the 27-day cycle), which began before the end of July, were exacerbated by the geomagnetic disturbance that occurred on August 2 3. The effects of this decline will still be felt in the ionosphere during the first third of August. The second third of the month will bring an improvement. Then, in the final third, when solar radiation levels will once again be elevated, the approaching fall will also have a noticeable and positive effect on the ionosphere.

The Predicted Planetary A Index for August 7 to August 13 is 5, 5, 5, 5, 8, 8, and 5 with a mean of 5.9. The Predicted Planetary K Index is 2, 2, 2, 2, 3, 3, and 2 with a mean of 2.3. Predicted 10.7 centimeter flux is 110, 105, 105, 105, 105, 105, and 110 with a mean of 106.4.

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 this:

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

"Understanding Solar Indices" from September 2002�QST.


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

08/17/2026

Weekly Highlights and Forecast, August 17, 2026, by NOAA Space Weather Prediction Center:

Solar activity ranged from very low to low levels throughout the
period. No R1 (Minor) or greater events were observed. The largest
flare was a C8.2/Sn at 16/1928 UTC from Region 4506. An associated
CME was observed in LASCO C2 imagery following the C8.2 flare, but
analysis is ongoing in order to determine any Earth-directed component.
Other activity included the lift-off of av large filament near S16E22
at 14/0332 UTC which produced a CME that is expected to arrive on 17-18 Aug.

Geomagnetic field activity is expected to reach active levels on
17-18 Aug due to the anticipated arrival of a CME that left the Sun
on 14 Aug. Active conditions are expected again on 21-22 Aug and 04
Sep due to the influences of a CH HSS. Quiet and quiet to unsettled
conditions are expected to prevail throughout the remainder of the
outlook period.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, August 13, 2026, by F. K. Janda, OK1HH:

It appears that solar activity will remain relatively low for a few more days before mid-August; however, it is more likely that July s surprise will repeat itself and solar activity will increase after a few days. This would be a more favorable scenario for possible future developments in the Earth s ionosphere. Although the sporadic E layer often plays a significant role in the ionosphere at mid-latitudes, its season will gradually come to an end.

Solar activity will rise in the second half of the month, while geomagnetic activity is expected to decrease on average. It is hard to imagine a better scenario for future developments, and it appears that this one will at least partially come to pass.

The current solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=7od5srHvDsw&t=3s[1] .

The Predicted Planetary A Index for August 14 to August 20 is 5, 5, 5, 15, 12, 20, and 8 with a mean of 10. The Predicted Planetary K Index is 2, 2, 2, 4, 4, 5, and 3 with a mean of 3.1. Predicted 10.7 centimeter flux is 95, 95, 95, 100, 105, 105, and 105 with a mean of 100.

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 this:

https://bit.ly/3Rc8Njt[6]

"Understanding Solar Indices" from September 2002�QST.


[1] https://www.youtube.com/watch?v=6SoYfTnrudc
[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS

08/28/2026

Solar activity reached moderate levels this week. Region 4513 was responsible for an M2.2/1B flare that reached its peak on August 26. This event was accompanied by a 10.7-centimeter radio burst that reached 140 solar flux units (SFU) and a type II radio sweep with an estimated shock speed of 930 km/s despite its relatively impulsive nature. No resulting coronal mass ejection (CME) has been observed in available coronagraph imagery as of the time of this report.
�
Other activity of note since the last reporting period included an easterly CME first seen in two LASCO C2 coronagraph imageries on August 25.
�
The first event likely originated from the vicinity of Region 4513 around August 25 while no definitive source could be identified with any confidence for the latter. Nevertheless, both of these events are currently being modeled and assessed to determine the presence of an Earth-directed path.
�
Solar activity will likely remain at minor-moderate (R1-R2) levels, with a slight chance for strong (R3) activity, through August 28, mostly due to the flare history and potential of Region 4513.
�
Solar wind parameters were at undisturbed levels with solar wind speeds between ~300-340 km/s, total field at or below 5 nT and Bz northward or near neutral. Phi angle was predominantly negative.
�
Nominal solar wind conditions are expected to continue until midday August 27, when the onset of a positive polarity coronal hole high speed stream (CH HSS) influence is anticipated. Additional solar wind disturbances, with increased solar wind densities and total IMF, are likely on August 28 due to the impact of the CMEs that left the Sun on August 25.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, August 27, 2026, by F. K. Janda, OK1HH:

More or less in line with expectations, total solar activity has been slightly elevated during the last third of August, including flare activity we have been observing moderate-sized flares since August 24, peaking on August 25. Most sunspots and all larger groups are now located in the western half of the solar disk, which increases the likelihood of rising geomagnetic activity, which had been low for a relatively long period beginning on August 21. This resulted in above-average shortwave propagation conditions, including propagation in the Earth s polar regions.

Solar activity is expected to remain elevated for the remainder of August and will drop significantly in early September. Geomagnetic activity, however, will increase, whilst is likely to remain higher for the rest of August. Consequently, shortwave propagation conditions will no longer be as consistent as in recent days; instead, there will be a decrease in usable frequencies and an increase in attenuation. The beginning of September will be calmer, albeit with slightly lower critical frequencies in the F2 layer of the ionosphere.

The Predicted Planetary A Index for August 28 to September 3 is 10, 8, 5, 5, 5, 5, and 5 with a mean of 6.9. The Predicted Planetary K Index is 3, 3, 2, 2, 2, 2, and 2 with a mean of 2.3. Predicted 10.7 centimeter flux is 120, 120, 120, 120, 120, 120, and 115 with a mean of 119.3.
�

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 this:

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

"Understanding Solar Indices" from September 2002�QST


[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
---
� Synchronet � Whiskey Lover's Amateur Radio BBS