04/03/2026

Solar activity has been at low levels with only C-class flares
produced by Regions 4401, 4405, and 4409. There were 9 numbered
active regions on the solar disk, with 4409 showing the most
significant growth during the period and producing the largest flares
on April 1. A new region emerged but it has not yet been numbered.
ÿ
Multiple filaments erupted during the day on April 1, producing
coronal mass ejections (CMEs) observed in coronagraph imagery, but
their propagation modeling did not suggest impacts to Earth. The
exceptions are the ejecta first observed at GONG H-alpha images on
April 1.
ÿ
Solar activity is likely to reach moderate (R1/R2-minor/moderate)
levels, with a slight chance for X-class (R3-strong) flares through
April 4, due primarily to the flare potential of Regions 4404, 4405
and 4409.
ÿ
Solar wind parameters were near nominal levels with solar wind speed
averaging around 440 km/s.

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

The increase in overall solar activity during the third ten-day
period of March-albeit with a slight delay-led to a gradual rise in
MUF values, extending into the first days of April. An increase in
solar flare activity did not occur until April 30, beginning with a
flare at 0319 UT with an X-ray intensity of X1.4, which lasted a long
time and was accompanied by a CME. Since a large coronal hole No. 36
was located nearby, a significant increase in geomagnetic activity
was expected. This did not occur until April 2, but already during
several preceding active intervals, we could observe the effects of electromagnetic wave scattering on ionospheric inhomogeneities,
clearly visible even on ionograms.

Active region NOAA 4405, located 27 degrees south of the solar
equator, has been clearly visible for a week as the largest on the
solar disk and appears to be stable. On April 3, it passes the
central meridian, and its proximity to coronal hole No. 36 is a
potential source of intensified solar wind. It also indicates higher geomagnetic activity (at G2 level since April 2). This proximity will
likely be the cause of increased geomagnetic activity during the
first ten days of April. Consequently, this will lead to irregular
shortwave propagation conditions and more frequent drops in the MUF.

The next increase in solar activity will likely occur in the last
third of April. Daily MUF values will rise again, and at the same
time, a sporadic E layer will begin to appear occasionally in
mid-latitudes. Although it will not yet have a significant impact on
shortwave propagation, it will occasionally cause interesting DX
openings on the shortest shortwave bands.

The Predicted Planetary A Index for April 4 to April 10 is 22, 10,
15, 8, 7, 25, and 40 with a mean of 18.1. The Predicted Planetary K
Index is 5, 3, 4, 3, 2, 5, and 6 with a mean of 4. 145, 145, 135,
125, 118, 120, and 110 with a mean of 128.2

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[1]ÿand the ARRL Technical Information
Service web page at,ÿhttp://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]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[4]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[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

04/10/2026

Solar activity remained at low levels this week. Most of the C-class activity came from either Region 4414 or Region 4409, which has developed a delta spot in its intermediary area. All remaining spots were either stable or in slight decay, with Region 4406 rotating over the west limb by the end of the reporting period.
ÿ
Coronal activity was observed in CCOR-1, LASCO and STEREO available imagery during the period. Of the four eruptions, one was far-sided, one was too narrow plus too far north of the ecliptic to have any Earth-directed component, and two had the potential for Earth-directed components. The first was associated with a C2.4 flare from Region 4414 while there was no clear source for the second. Modeling indicates these eruptions will pass behind Earth's orbit and no impact is anticipated. Eruptions potentially associated with the C8.9 are currently being analyzed. Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was on Apr 9th 2026 at 08:45 UTC.
ÿ
Solar activity is expected to be at low levels over April 9 to 11, with a chance for M-class (R1-R2/minor-moderate) flares and a slight chance for X-class (R3/strong or greater) flares, driven primarily by the flare potential of Regions 4409 and 4414. The greatest expected 3 hr Kp for Apr 09 through Apr 11 2026 is 5 (.33NOAA scale G1).

A brief description of Sunspots can be found on the Space Weather
Prediction Center website at, https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle[1]ÿ.
ÿ
Solar wind parameters reflected the transition out of a waning negative polarity coronal hole high speed stream (CH HSS) into nominal conditions. Wind speeds continued to decline from a peak of ~500 km/s to near 400 km/s by the end of the period.

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

Perhaps the biggest surprise in recent days was that, following the geomagnetic disturbance of April 2-3 (which had been expected, albeit a day earlier and with lower intensity), there were no further major surprises. Solar activity declined as predicted, whereas because it declined over a relatively long period, there was a greater-than-expected drop in critical frequencies in the F2 ionospheric region at mid-latitudes.

For forecasting developments in the second third of April, the 27-day cycle could serve as a relatively reliable guide this time. First of all, one might expect a one- to two-day increase in geomagnetic activity (which is also indicated by the presence of solar coronal holes near the central meridian), followed by relative calm. This is despite the short time that has elapsed since the eleven-year peak of solar activity.

The Predicted Planetary A Index for April 4 to April 10 is 5, 4, 3, 2, 2, 2, and 2 with a mean of 2.8. The Predicted Planetary K Index is 18, 10, 8, 7, 5, 4, and 7 with a mean of 8.4. 10.7 centimeter flux is 106, 105, 108, 110, 115, 115, and 120 with a mean of 111.2.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2]ÿand the ARRL Technical Information
Service web page at,ÿhttp://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]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[5]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[1] https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle
[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

Test reply via API

---
þ Synchronet þ MSmac BBS - msmacbbs.maletazul.pt

04/17/2026

Solar activity was at very low levels with only isolated B-class
flaring, mostly from Region 4416.
ÿ
There are currently four numbered regions on the visible disk. Region
4416 remains the largest group by area but exhibited signs of
structural weakening, including flux submergence and a slight decay
of its intermediary pores. Region 4419 was the most complex group on
the disk and showed flux emergence, growth, and divergence within its intermediary spots, leading to the development of a mixed-polarity
gamma configuration. Region 4418 is trending toward plage with only
two small bipolar pores remaining and Region 4415 remained stable.
CMEs observed in coronagraph imagery were determined to be directed
away from Earth.
ÿ
Solar wind parameters reflected waning coronal hole high speed stream influences toward a nominal regime. Solar wind speeds underwent a
gradual, albeit erratic, decline from early-period highs near 420
km/s, to stabilize around 375 km/s by the end of the reporting
period. The phi angle was predominantly oriented in a positive (away
from the Sun) direction.
ÿ
Solar wind parameters are expected to remain primarily near nominal
levels through April 16. Significant enhancements are anticipated on
April 17 with the onset of a co-rotating interaction region (CIR)
that will precede the arrival of a negative polarity high-speed
stream (-CH HSS).
ÿ
Spaceweather.com[1] reports a large hole has opened in the sun's
atmosphere, and it is directly facing Earth. High-speed solar wind
flowing from this coronal hole should arrive on April 18th,
potentially sparking G2-class geomagnetc storms.

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

It is as if we were not just past the 11-year solar activity maximum;
the solar flux fell and remained below 100 s,f,u for five days (April
9-13), while the number of sunspot groups dropped to just three.
Flare activity declined similarly. However, more significant for the
future development of solar activity-and especially for its impact on
Earth-is the large coronal hole No. 42, which is approaching the
central meridian from the northeast. Its western borderÿ can be
considered a potential source of solar wind that will reach Earth in
the coming days.

Initially, it seemed that this would not happen until April 19, but
closer observation of its development shows that the Earth will be
hit by a fast solar wind as early as April 18 during the day. Or
perhaps as early as the late afternoon of April 17, in which case the disturbance could begin with a positive phase (with an increase in
MUF) while shouldÿ continue through the negative phase for much of
the weekend.

The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube.
https://www.youtube.com/watch?v=cOcV9xp8qU8&pp=0gcJCdMKAYcqIYzv[2]

The Predicted Planetary A Index for April 18 to April 24 is 15, 20,
12, 10, 8, 5, and 8 with a mean of 11.1. The Predicted Planetary K
Index is 3, 4, 4, 3, 3, 2, and 3 with a mean of 3.1. 10.7 centimeter
flux is 110, 110, 120, 130, 140, 145, and 145 with a mean of 128.5.
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3]ÿand the ARRL Technical Information
Service web page at,ÿhttp://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]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[6]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[1] http://spaceweather.com
[2] https://www.youtube.com/watch?v=cOcV9xp8qU8&pp=0gcJCdMKAYcqIYzv
[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

04/24/2026

Solar activity remained at low levels this past week with numerous C1
flares from Region 4420, which exhibited growth during the period.
Region 4419 showed minor decay, particularly in its trailing spots,
while producing a lone C1.0 flare. Region 4422 was numbered during
the period but remained inactive. No Earth-directed CMEs were
observed in coronagraph imagery.

Solar activity is expected to continue at low levels, with a slight
chance for isolated M-class activity, through April 24, primarily due
to the flare potential from Region 4420 and limb activity.

Solar wind parameters reflected waning coronal hole high speed stream
(CH HSS) influences. The wind speed maintained an average of 525
km/s, and Phi was predominantly in a negative orientation towards the
Sun.

Region 4419ÿ was the most active region of the period, responsible
for 5 out of the 7 C-class flares observed during the week, including
the largest one: a C4.1. The remainder 2 C-class flares of the period
were a C1.1 from Region 4414 and a C1.6 from Region 4416. Coronal
activity was observed during the week with some filament eruptions
and few CMEs without Earth-directed components.

Spaceweather.com[1] reports the sun has been quiet for weeks. That ended
today with two powerful X-class solar flares. In quick succession,
sunspot 4419 unleashed X2.4 (0107 UT) and X2.5 (0813 UT) explosions.

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

Although solar activity during the first four months of this year was
lower than in the previous two years of the 11-year solar maximum
(2024-2025), this was anything but a continuing decline. Periods of
low solar activity gradually tended to lengthen and were interspersed
with sudden increases in both overall and eruptive activity. This
trend is very clearly evident in the solar flux, which was very low
during the penultimate solar cycle (March 14-21), followed by a
further and longer decline shortly after the beginning of April and particularly between April 9 and 13.

Moreover, during the long period of low solar activity (April 5-22), geomagnetic field activity increased (April 18-21), further
diminishing hopes for the usual seasonal improvement in shortwave
propagation conditions. However, two sunspot groups then emerged on
the eastern limb of the solar disk, bringing their total number to
four. Then came Thursday, April 23, with several moderately powerful
solar flares, alternating between the east and west of the solar
disk, preceded by rapid changes in magnetic configuration where the
eruptions were soon observed.

Therefore, in the coming days we will continue to observe increased
solar activity and the potential effects of fast solar wind on Earth.
Shortwave propagation conditions will vary irregularly, while during
the ongoing bursts of intense solar wind, ionospheric attenuation
will increase at higher latitudes.

The Predicted Planetary A Index for April 25 to May 1 is 8, 5, 5, 5,
20, 18, and 12 with a mean of 10.4. The Predicted Planetary K Index
is 3, 2, 2, 2, 5, 5, and 4 with a mean of 3.3. 10.7 centimeter flux
is 115, 120, 125, 125, 125, 125, and 125 with a mean of 122.9.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[2]ÿand the ARRL Technical Information
Service web page at,ÿhttp://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]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[5]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[1] http://spaceweather.com/
[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

05/08/2026

Solar activity was at low levels this past week with occasional
B-class and isolated low-level C-class flares. The largest event of
the period was a C1.4/Sf flare from Region 4429 on May 5.

There are currently six numbered regions on the visible disk as 4434
decayed to plage and Region 4428 rotated beyond the western limb as
an E-type group. The remaining regions mostly showed signs of decay.
Region 4425 appeared stable, though full characterization is
difficult due to extreme limb proximity. Region 4429 showed continued submergence and decay, decreasing in both area and length along with
a total loss of penumbra.

Region 4431 showed some minor new development, with a few small spots
emerging in both polarities following recent decay. Region 4432 had
minor emergence in its intermediate spots, despite an overall gradual
decrease in extent. The remaining regions were mostly stable.

No Earth-directed CMEs were observed in available coronagraph

Flare probabilities increase beginning May 8 as up to two active
regions rotate into view from beyond the eastern limb.
Considering the size of these regions and recent far-side eruptions
seen in coronagraph imagery, solar activity is expected to increase
May 8 - 9 with a chance for M-class (R1-R2/minor-moderate) flares and
a slight chance for X-class (R3/strong or greater) flares.

Solar wind parameters returned to near background levels as transient
coronal mass ejection (CME) influences waned. Solar wind speeds
averaged around 375 km/s. The phi angle was predominantly in a
positive (away) orientation for the majority of the period with a few short-lived oscillations into a negative (toward) orientation during
the period.

Spaceweather.com[1] reports a big and active sunspot hiding behind the
sun's northeastern limb is about to reveal itself, rotating into view
this weekend. A dramatic M2-class solar flare on May 7th confirmed
its approach. The unnamed sunspot has produced at least 5 CMEs in
recent days. If this production continues, Earth could soon be in
line for a solar storm.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere,ÿ May 7, 2026, by F. K. Janda, OK1HH:

Overall solar activity declined slowly but steadily in late April and
early May. Eruptive activity was low, with active regions mostly and
featuring a simple magnetic field configuration. Geomagnetic activity
increased significantly only on May 4, after which the polarity of
the longitudinal component of the interplanetary magnetic field
returned to positive values. The ionosphere returned to a state
favorable for shortwave propagation since May 6.

Solar activity is likely to remain at current levels, while should
decline shortly and slightly in mid-May. Geomagnetically quiet days
can be expected starting May 10 again. Prior to that, there will be a
slight increase in activity, likely on May 8. No other significant
fluctuations are likely.

The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube. https://www.youtube.com/watch?v=lNcaoB7be-k[2]

The Predicted Planetary A Index for May 9 to May 15 is 10, 6, 5, 5,
5, 5, and 25 with a mean of 8.7. The Predicted Planetary K Index is
3, 2, 2, 2, 2, 2, and 5 with a mean of 2.6. 10.7 centimeter flux is
130, 130, 125, 125, 120, 115, and 120 with a mean of 123.6.
ÿ

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[3]ÿand the ARRL Technical Information
Service web page at,ÿhttp://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]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[6]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[1] http://Spaceweather.com
[2] https://www.youtube.com/watch?v=lNcaoB7be-k
[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

05/29/2026

Solar activity has remained at low levels this past week. The largest event of the period was a C3.4 flare originating from Region 4446.ÿ

Solar activity has remained at low levels this past week. The largest event of the period was a C3.4 flare originating from Region 4446.ÿ ÿ There are nine numbered regions on the visible disk. Region 4452 showed notable growth and new flux emergence. Region 4450 decayed to plage, though unassociated transitory pores were observed to its east and west. Region 4443 decayed into a unipolar spot as it approached the west limb following the loss of its leading components. Regions 4453, 4454 and 4455 were numbered during the period. Far-side satellite imagery from Solar Orbiter indicates that Region 4455 is likely a large bipolar group with its trailing opposite-polarity spots still located behind the east limb and was numbered proactively due to its flaring potential. All other regions either continued in slow decay or remained stable. A faint, potentially partial-halo, coronal mass ejection (CME) first seen in LASCO C2 imagery on May 26 and subsequently in GOES/CCOR1 was analyzed. No obvious on-disk source exists. Modeling suggests a possible glancing blow at Earth on May 31. Additionally, narrow eruptions associated with flaring from newly numbered Region 4444 were seen in SUVI imagery but these features are well northward of the ecliptic plane with no Earth-directed components. No other Earth-directed coronal mass ejections (CMEs) were observed in available coronagraph imagery. ÿ Solar activity is expected to be at low to moderate levels through May 30. There remains a chance for isolated M-class flares (R1-R2/minor-moderate) driven by the eruptive potential of the southeast sunspot groups and newly numbered Region 4454. ÿ Solar wind parameters remained slightly elevated and possibly indicative of weak negative polarity coronal hole high-speed stream (-CH HSS)influences.ÿ ÿ Solar wind speeds varied modestly between 350 and 425 km/s. The phi angle was predominantly in the negative sector (towards the Sun), though minor deviations were observed later in the period. ÿ Solar wind parameters are expected to remain mildly enhanced due to weak coronal high speed stream (-CH HSS) influences through May 29. A return toward near-background, nominal conditions is anticipated by May 30. Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, May 28, 2026 ÿ Observations of the far side of the Sun by the Solar Orbiter probe showed us how a new and relatively large active region was approaching the northeastern limb of the solar disk. But it wasn't until it began to emerge on May 28 (designated as AR 4455) that it became clear the recent rise in solar activity would continue. Furthermore, the only significant coronal hole in the higher northern heliographic latitudes is sufficiently far from other active regions, so we need not expect a significant intensification of the solar wind. Therefore, we could expect calmer conditions in the Earth's magnetosphere and, at the same time, higher usable frequencies in the ionosphere for long-distance communications before their seasonal decline. However, summer in the ionosphere of the Earth's northern hemisphere, with higher attenuation in the lower ionosphere during the long days, will often be enlivened by sporadic E layers in the mid-latitudes until August. ÿ 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
---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS

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.
ÿ
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.
ÿ
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.
ÿ
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.
ÿ
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]ÿand the ARRL Technical InformationÿService web page at,ÿhttp://arrl.org/propagation-of-rf-signals[2]. Forÿan explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[4]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[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

07/10/2026

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]ÿand the ARRL Technical InformationÿService web page at,ÿhttp://arrl.org/propagation-of-rf-signals[2]. Forÿan explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[4]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[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

07/20/2026

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.
ÿ
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.
ÿ
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.
ÿ
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.
ÿ
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,ÿ 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]ÿand the ARRL Technical InformationÿService web page at,ÿhttp://arrl.org/propagation-of-rf-signals[2]. Forÿan explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[4]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST.


[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

07/24/2026

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.
ÿ
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.
ÿ
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.
ÿ
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.
ÿ
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.
ÿ
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]ÿand the ARRL Technical InformationÿService web page at,ÿhttp://arrl.org/propagation-of-rf-signals[2]. Forÿan explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[3]ÿ. Information and
tutorials on propagation can be found at,ÿhttp://k9la.us/[4]ÿ.

Also, check this:

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

"Understanding Solar Indices" from September 2002ÿQST


[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