05/30/2025

Solar activity reached moderate levels early this past week with
several flares. An X1-class flare erupted mid-week, but activity has
slowed down with the majority of the low-level C-class flares. A
coronal mass ejection (CME) was observed on May 27 with a flare from
Region AR4100.

Modelling determined the CME to be well behind Earth's orbit. No
other potentially Earth-directed CMEs were detected in available
coronagraph imagery. M-class flare activity, minor - moderate, is
likely, with a slight chance for X-class flare events, strong or
greater, through May 30.
ÿÿ
The forecast of Solar and Geomagnetic Activity to June 21, 2025:

Solar activity is likely to reach moderate levels
(R1-R2/Minor-Moderate), with a chance for R3 (Strong), over the next
three days as Region AR4098, the most productive region on the
visible disk, makes its way to the west limb of the Sun. A chance
for M-class X-ray activity (R1-R2) will persist throughout the
outlook period due to multiple regions on the visible as well as
multiple active regions scheduled to return from the far side of the
Sun.

No proton events are expected at geosynchronous orbit.

The Geomagnetic field activity is expected to be at a mostly
elevated level due to anticipated influence from multiple, recurrent
coronal holes. G1 (minor) geomagnetic storms are likely on June
13-14; active conditions are likely over June 2, June 5, June 10 and
11, and June 15 to 17.

Unsettled conditions are likely over June 3 and 4, June 6 and 7, and
June 18 to 21.ÿ Quiet conditions are only expected on June 8 and 9.

On May 30, Spaceweather.com[1] reports on a Super-Fast Solar Wind, and
a 24-hour Geomagnetic Storm.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - May 29, 2025, from F. K, Janda, OK1HH:

"On May 29, geomagnetic activity reached the level of a strong storm
(Kp 7) worldwide, which came as no surprise to those who had been
monitoring the recurring disturbances during the last four solar
rotations, and especially the developments on the Sun over the last
five days or so.

"Solar flares were observed, only occasionally with coronal mass
ejections (CMEs). Although the large coronal hole in the southwest
of the solar disk disappeared, other coronal holes appeared across
the solar disk in the meantime. The largest of these extends from
the southwest to the northeast and has been crossing the central
meridian since May 26. It has negative polarity and is associated
with the arrival of a high-speed stream (up to about 730 km/s). Even
in the coming days, after the current disturbance subsides, mild
active storm conditions (Kp 4) will continue.

"Overall solar activity will increase slightly in the coming days,
and geomagnetically active days will alternate irregularly with
calmer ones. Ionospheric conditions for shortwave propagation will
improve, but at best only to average levels."

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.

The Predicted Planetary A Index for May 31 to June 6 is 8, 10, 12,
8, 10, 12, and 10, with a mean of 10.ÿ The Predicted Planetary K
Index is 3, 3, 4, 3, 3, 4, and 3, with a mean of 3.3.ÿ Predicted
10.7 centimeter flux is 125, 120, 115, 110, 110, 115, and 120, with
a mean of 116.4.
ÿ


[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

06/06/2025

Solar activity remained at moderate levels earlier this week. There
was an approximately 20-degree filament eruption on June 4 and a
possibly related Coronal Mass Ejection (CME). The CME is unlikely to
have an Earth-directed component, but analysis is in progress.

The geomagnetic field is expected to be quiet to unsettled on June 7
as High Speed Stream (HSS) activity continues. G1 (Minor) storm
levels are likely with the anticipated onset of a CME - that left
the Sun on June 3 - around mid-to-late on June 7. On June 8,
unsettled to active levels are expected.

Unsettled to active conditions are likely June 10 to 12 due to
recurrent negative polarity Coronal Hole High Speed Stream (CH HSS)
influences. Unsettled to G1 (Minor) conditions are likely on June 13
to 22 due to positive polarity CH HSS influences. Unsettled to G1
(Minor) conditions are likely on June 23 to 28 due to negative
polarity CH HSS influences.

Solar activity is expected to be low with a chance for M-class
flares (R1-R2/Minor-Moderate) and a slight chance for an X-class
flare (R3-Strong) on June 7.
ÿ
Solar wind speed parameters increased from approximately 550 km/s to
nearly 810 km/s before decreasing to around 760 km/s. This could
either be transient influence or a transition back into the Coronal
Hole High Speed Streams.
ÿ
Quiet to active levels are expected to prevail on June 7.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - June 5, 2025, from F. K. Janda, OK1HH:

"When assessing solar activity based on the sunspot, or more
modernly based on the intensity of solar radio noise, we can
tentatively conclude that the maximum of the 25th cycle occurred
last spring and summer, or early autumn (the highest smoothed
sunspot number was in October 2024: R12 = 160.8, and then declined).
Even so, it was much higher than most astronomers had predicted.

"But that's not the end of the story. In May of this year in
particular, there was a surprising increase in the number and energy
of particles in the solar wind, especially during larger solar
flares. Particle ionization also affects the Earth's ionosphere,
although not as nicely as we would like given the state of the
Earth's ionosphere. In short, shortwave propagation conditions were
rarely good during May and especially early June 2025. They were
mostly unstable, disrupted, with irregular daily cycles and frequent occurrences of increased attenuation.

"An exceptional phenomenon is the so-called Forbush effect, also
known as the 'Forbush decrease' in the intensity of galactic cosmic
rays after the arrival of a CME in the vicinity of Earth. The
largest decrease in cosmic ray intensity in more than 20 years, by
as much as 25%, was recorded on June 1, 2025 (the last time this
happened was on October 30, 2003). Particles ejected by the Sun will
remain in our vicinity and reduce the intensity of cosmic rays of
galactic origin for another week or two.

"A decline is generally expected in the further development of solar
activity. Only optimists admit that there will be one more increase
this year, probably in the northern half of the solar disk."

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.

The Predicted Planetary A Index for June 7 to 13 is 10, 8, 5, 15,
12, 10, and 35, with a mean of 13.6.ÿ Predicted Planetary K Index is
3, 3, 2, 4, 4, 3, and 6, with a mean of 3.6.ÿ Predicted 10.7
centimeter flux is 155, 155, 155, 155, 150, 150, and 155, with a
mean of 153.6.

ÿ


[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

06/13/2025

On Friday, June 13, Spaceweather.com[1] reports a CIR, or co-rotating interaction region, hit Earth's magnetic field, sparking a G2-class
geomagnetic storm. There is a chance that this ongoing storm could
intensify to category G3 (Strong).

Overall, solar activity was at low levels, with only C-class flares
observed the past 48 hours. There were flares observed beyond the
east limb, but no responsible region has yet come into view. Flaring
was also observed just before 0600 UTC June 12 from near region
AR4105 and while modeling is not yet complete, is not expected to
have an Earth-directed component. All other regions were mostly
quiet and stable in their size.

Moderate geomagnetic storming returns on June 14, with a slight
chance for G3 (Strong) levels, due to recurrent positive polarity CH
HSS influence. By June 15, conditions are anticipated to slowly
diminish as CH/CME effects weaken, resulting in periods of G1
(Minor) geomagnetic storming.

A gradual trend towards a less disturbed solar wind environment is
expected to transpire.ÿ By June 14, positive polarity Coronal Hole
High-Speed Stream influences are expected to begin with elevated
conditions likely to linger into June 15.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, June 12, 2025, by F. K. Janda, OK1HH:

"The observed number of sunspot groups ranged between five and six
until June 10. A change occurred on June 11, when four more groups
appeared in the northeast of the solar disk, followed immediately by
a fifth. Which quickly manifested itself in a slight increase in
solar flux. However, since the afternoon of June 11, the activity of
the Earth's magnetic field increased, so therefore a noticeable
decrease in MUF followed on June 12.

"Fortunately, propagation conditions in the shortwave DX bands
(usually understood to mean frequencies above 14 MHz) were
diversified by the more frequent occurrence of the sporadic-E layer.
Although irregular and with only short rises in MOF Es towards 30
MHz, it revived the DX bands despite the decline in MUF F2 (by up to
several MHz during the day).

"Solar activity will temporarily increase slightly in the second
half of June, but this will have little effect on shortwave
propagation conditions. There is greater hope for a slight
improvement and more interesting developments from mid-June onwards.
However, shortwave propagation conditions in the last days of the
month will again be less regular and slightly disrupted."

For customizable propagation charts, visit the VOACAP Online for Ham
Radio website at, https://www.voacap.com/hf/[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 June 14 to 20 is 32, 22, 15, 12,
10, 8, and 8, with a mean of 15.3.ÿ The Predicted Planetary K Index
is 6, 5, 4, 4, 3, 3, and 3, with a mean of 4.ÿ Predicted 10.7
centimeter flux is 120, 118, 120, 120, 125, 130, and 130, with a
mean of 123.3.

ÿ


[1] http://Spaceweather.com
[2] https://www.voacap.com/hf/
[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

06/20/2025

On Friday, June 20, Spaceweather.com[1] reports that, in addition to it
being the first day of Summer in the Northern Hemisphere, on June 19
the Sun produced another X-class flare causing a shortwave radio
blackout over the Pacific Ocean.

Solar activity reached high levels when Region AR4114 produced the
strongest event of the period, an X1.9 flare at 2350 UTC. The region
remained the most complex on the disk despite being in a decay
phase. The other numbered spotted regions on the visible disk were
either mostly stable or in gradual decay. No Earth-directed CMEs
were observed in available coronagraph imagery.

R1 to R2 (Minor-Moderate) radio blackouts are likely with a chance
for X-class flares (R3-Strong) through June 21, mostly driven by the
potential from Regions AR4114, AR4115, and AR4117.

Coronal Hole High Speed Stream conditions are expected to persist
with waning influences into June 21.ÿ Unsettled conditions are
expected to continue.

Solar wind parameters continued to reflect a positive polarity CH
HSS (Coronal Hole High Speed Stream) regime.

The geomagnetic field is expected to be at quiet to unsettled levels
on June 21, and at quiet levels on June 22.ÿ Geomagnetic field
activity is likely to reach G1 (Minor) storm levels on June 25 and
26 due to negative polarity CH HSS influences.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, June 19, 2025, by F. K. Janda, OK1HH:

"Solar activity is still at the peak of its eleven-year cycle, even
though it reached its maximum last summer (with a monthly average of
R = 216 in August last year and a smoothed average of R12 = 160.8
for October last year). The change from last year is the shift of
sunspot activity from the southern to the northern half of the solar
disc. The appearance of new sunspot activity in the southeast in
recent days, close to the solar equator, came as a slight surprise.

"This Spring, especially in May and early June, we could not fail to
notice frequent periods of solar wind intensification and,
consequently, a number of geomagnetic disturbances, which caused the
critical frequencies of the ionospheric F layer to drop to values
corresponding to significantly lower solar activity. In recent days,
there has been only a slight improvement.

"Most forecasts for future solar activity predict a continuing
decline, but if we assume higher activity in the currently setting
sunspot groups, we can expect an increase after their appearance on
the north-eastern limb of the solar disc in July. Overall, calmer
conditions can be expected during the coming Summer, although
shortwave propagation conditions will continue to be slightly worse
than would correspond to the level of solar activity."

The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, https://www.youtube.com/watch?v=3RXJT7qLT0A[2] .

For customizable propagation charts, visit the VOACAP Online for Ham
Radio website at, https://www.voacap.com/hf/[3] .

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[4] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[5]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[6] . Information and
tutorials on propagation can be found at, http://k9la.us/[7] .

Also, check this:

https://bit.ly/3Rc8Njt[8]

"Understanding Solar Indices" from September 2002 QST.

The Predicted Planetary A Index for June 21 to 27 is 5, 5, 8, 12,
25, 20, and 15, with a mean of 12.9.ÿ Predicted Planetary K Index is
2, 2,3, 4, 5, 5, and 4, with a mean of 3.6.ÿ 10.7 centimeter flux is
138, 135, 125, 125, 130, 125, and 125, with a mean of 129.

ÿ


[1] http://Spaceweather.com
[2] https://www.youtube.com/watch?v=3RXJT7qLT0A
[3] https://www.voacap.com/hf/
[4] http://www.arrl.org/propagation
[5] http://arrl.org/propagation-of-rf-signals
[6] http://arrl.org/the-sun-the-earth-the-ionosphere
[7] http://k9la.us/
[8] https://bit.ly/3Rc8Njt

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

06/27/2025

Solar activity has been at low levels for the past 48 hours, with
low-level C-class flares.
ÿ
There was a narrow coronal mass ejection (CME), likely associated
with minor flaring from Regions AR4117 and AR4118 between 1439 UTC
and 1524 UTC on June 24. Initial modeling indicated a miss, south
and behind Earth's orbit. However, it should be noted that analysis
of this event is low confidence given the assumed source location.
ÿ
An enhanced solar wind environment is expected to continue through
June 28 under a negative polarity Coronal Hole High-Speed Stream
regime before beginning to trend towards a more nominal environment
on 29 June.

There is a chance for R1-R2 (Minor-Moderate) events through June 29.
There is also a slight chance for an R3 (Strong) or greater event
through June 29, as well as a slight chance for S1 (Minor) solar
radiation storm conditions through the reporting period.

Geomagnetic field activity is likely to reach active levels on July
1 to 3, 05 and 6, and 11 and 12, all due to recurrent CH HSS
influences. Quiet, and quiet to unsettled conditions are expected to
prevail throughout the remainder of the period through July 19.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - June 26, 2025, by F. K. Janda, OK1HH:

"The last significant solar flare was recorded on June 15, reaching
an X-ray brightness of M8.4, while ejecting a CME into space. The
particle cloud arrived at Earth on June 18, with the subsequent
increase in solar wind speed, which caused an improvement in
propagation conditions in the lower shortwave bands.

"Although eruptions with higher X-ray brightness were also recorded,
they only caused shorter attenuation in the lower layers of the
ionosphere on the illuminated part of the Earth.

"Overall solar activity declined steadily after June 15, with five
to six visible sunspot groups. At most two were capable of producing
larger eruptions.ÿ Their proximity to two of the three observable
coronal holes near the equator made it possible to predict an
intensification of the solar wind and the occurrence of geomagnetic disturbances for June 25-26 (or possibly also June 27).

"This was all the more likely given that it was the central meridian
region. Since then, however, the sunspot groups and coronal holes
have shrunk. The increase in solar wind speed (up to 700 km/s) and
geomagnetic activity (only G1) was therefore smaller. However, the
flux of electrons with energies above 2 MeV reached high values,
with a maximum flux of 1,260 pfu at 25/1355 UTC.

"Unfortunately, an increase in the concentration of free electrons
in the Earth's ionosphere is a relatively common phenomenon this
year and worsens the conditions for shortwave propagation.

"A return to background levels is expected from June 28. In July,
larger sunspot groups will return to the solar disk. Therefore, the
solar flux will rise slightly during the first ten days. Only a very
slight improvement in shortwave propagation conditions can be
expected in the summer ionosphere of the Earth's northern
hemisphere."

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.

The Predicted Planetary A Index for June 28 to July 4 is 15, 10, 5,
15, 15, 12, and 5, with a mean of 11.ÿ Predicted Planetary K Index
is 3,3, 2, 4, 4, 4, and 2, with a mean of 3.1.ÿ 10.7 centimeter flux
is 140, 145, 145, 140, 140, 140, and 145, with a mean of 142.1.

ÿ


[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