04/11/2025

Due to most of the regions on the solar disk being fairly simple in
their magnetic complexity, solar activity is expected to remain at
low levels with a chance for M-class flares (R1 to R2, or Minor to
Moderate).

Solar wind parameters are expected to trend further towards nominal
levels as the Coronal Hole High-Speed Stream effects continue to
wane.

Additional enhancements from another negative polarity Coronal Hole
is likely on April 12, combined with potential effects from the
glancing blow of a Coronal Mass Ejection that left the Sun on April
8.ÿ Elevated conditions are likely to continue through April 13 as
the influences persist of the Coronal Hole.

Solar activity has been at moderate levels for the past 24 hours.
There are currently 8 numbered sunspot regions on the disk.ÿ Solar
activity is expected to be low with a chance for M-class flares on
April 12.

The long range forecast of Solar and Geomagnetic Activity for April
12 to May 3:

The declining trend in solar flux and activity is expected to bottom
out around April 15, after which a slowly increasing period is
expected. The anticipated return on April 22 of the active
longitudes that gave rise to Region AR4046 (responsible for X-flare
activity) should bring solar activity to moderate and occasionally
high levels through the end of the forecast period.

No proton events are expected at geosynchronous orbit until the
expected increase in flare activity beginning on April 22. Then
there will be an increasing chance for an isolated proton event as
the more potent regions approach the west limb by the end of the
forecast period.

Flux will subside to moderate levels after April 12 as the effects
from the fast stream wane. April 19 is expected to bring a return to
high levels, again in response to another recurrent fast stream. The
elevated conditions are expected to remain through April 28 before
returning to moderate levels.

Geomagnetic field activity is expected to be primarily quiet to
unsettled, with an isolated active period, until the return of a
recurrent geoeffective coronal hole between April 19 to 21. Active
conditions are expected to prevail through April 24 before the fast
solar wind stream wanes.

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 April 12 to 18 is 12, 12, 12, 8,
5, 5, and 5, with a mean of 8.4.ÿ The predicted Planetary K Index is
3, 3, 3, 3, 2, 2, and 2, with a mean of 2.6.ÿ Predicted 10.7
centimeter flux is 140, 140, 140, 135, 140, 140, and 145, with a
mean of 140.

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

04/18/2025

Spaceweather.com reports a Cannibal Coronal Mass Ejection on April 15 sparked geomagnetic storms.ÿ On April 16, the storm became severe (G4) with Northern Lights sighted as far south as France.ÿ The storm is subsiding now to a category G1/G2, which could still produce high-latitude auroras.

Although Regions AR4062 and AR4064 have been relatively quiet they are more structurally complex than anticipated.ÿ They will maintain a 60 chance for R1-R2 (Minor-Moderate) flare activity through April 19.ÿ Chances for X-class (Strong) flare activity remain around 10.

Unsettled to active levels are expected on April 18 followed by quiet to unsettled conditions on April 19.

Solar activity is expected to be at moderate to high levels on April 27 to May 10 with the return of Region AR4055.ÿ Low to moderate levels are expected for the remainder of the outlook period. Unsettled to active levels are expected on April 18, April 22 and 23, and on May 3 and 4.

G2 (Moderate) storm levels are expected again on May 2 due to recurrent Coronal Hole High-Speed Stream influences.ÿ G1 (Minor) storm levels are expected on May 1, and May 5 and 6, all due to recurrent Coronal Hole High-Speed Stream activity.

The latest report from Dr. Tamitha Skov, WX6SWW, can be found on YouTube at: https://www.youtube.com/watch?v=zpyPrcMKvTY[1] .

The Predicted Planetary A Index for April 19 to 25 is 10, 8, 8, 15, 15, 15, and 10, with a mean of 11.6.ÿ The Predicted Planetary K Index is 3, 3, 3, 4, 4, 4, and 3, with a mean of 3.4.ÿ 10.7 centimeter flux is 145, 145, 150, 155, 155, 160, and 165, with a mean of 153.6.

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]. ÿ

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


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

04/25/2025

Solar activity has been at low levels with only minor C-class
flaring through April 24, 2025, and is expected to be moderate with
a chance of M-class flares (R1-R2, Minor-Moderate) through April 26.
No Earth-directed Coronal Mass Ejections (CMEs) have been observed.
A southwest CME was observed on April 23 and is considered to be
far-side due to the lack of any on-disk plasma motion/flare
activity.
ÿ
Solar wind parameters continued to be slightly enhanced due to the
Coronal Hole High-Speed Streams (CH HSS) associated with the
positive polarity coronal holes in the southern hemisphere.ÿ Solar
wind parameters are expected to continue to be influenced by
positive polarity, with CH HSS conditions through April 26.ÿ Nominal
conditions are expected thereafter.

On April 25, Spaceweather.com[1] reported the Earth was struck by an interplanetary shockwave on April 24 around 0700 UTC. An
interplanetary shock wave is an abrupt change in the solar wind -
probably caused by the Coronal Mass Ejection.

Overall, solar activity remained at low levels.ÿ Region AR4064
remained the largest sunspot group on the disk.ÿ The regions
intermediate spots grew in penumbral area over the past 24 hours.

The geomagnetic field is expected to remain at mostly quiet to
unsettled levels, with active conditions likely on April 27 due to
the influence from multiple positive polarity CH HSS.

There are currently 11 numbered sunspot regions on the solar disk.

Solar activity is expected to be low with a chance for M-class
flares on April 26 and 27.

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 April 26 to May 2 is 8, 8, 6, 6,
6, 25, and 35, with a mean of 13.4.ÿ The Predicted Planetary K Index
is 3, 3, 2, 2, 2, 5, and 6, with a mean of 3.3.ÿ Predicted 10.7
centimeter flux is 165, 165, 170, 170, 170, 170, and 175, with a
mean of 169.3.

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

05/02/2025

On May 2, Spaceweather.com[1] reported: "Astronomers are monitoring a
very large sunspot now turning toward Earth. Sunspot AR4079
stretches more than 140,000 km from end to end and has two dark
cores each large enough to swallow Earth. Moreover, it is surrounded
by a ring of Ellerman Bombs.

"Ellerman bombs are a sign of magnetic complexity in a sunspot.
Opposite polarities bump together, reconnect, and--boom! A
full-fledged flare may not be far behind."

Solar activity increased to moderate levels this past week. The
largest flare was on April 30 from an area where there was a major
M-class flare producer on its previous rotation last week.

No Earth-directed Coronal Mass Ejections (CMEs) were observed. Solar
activity is expected to be low with a chance for M-class flares
(R1-R2, minor-moderate), and a slight chance for X-class flares
(R3-strong) through May 2.
ÿ
Radio blackouts reaching the R1 levels were observed over the past
24 hours. The largest was on April 30.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - May 1, 2025, by F. K. Janda, OK1HH:

"In the past few weeks I have allowed myself to take a break because
I have been under the care of excellent doctors and caring nurses in
a top Prague hospital. Fortunately, I had a receiver available and
could and did use it occasionally, but the computer was at home, QRB
53 km away. Now I'm back and continuing my usual activities:
observing the events between the Sun and the Earth, analyzing the
context and trying to predict the future developments (yes, I know
that more accurate predictions are not possible, while I can well
justify why - but why not take science a bit as a sport too,
right...?).

"In the last few days of April, AR4079 rose on the northeastern limb
of the solar disk, while soon increased in area to over 1000
millionths. Already during the early months of this year, the Sun
had subtly hinted that the centre of gravity of activity might shift
from its southern to its northern hemisphere, but only now can we
see this trend more clearly. So, it's possible that we're in for
another upward swing within the current 11-year cycle, with active
regions mostly north of the equator. This could hold the promise of
improved ionospheric shortwave propagation conditions this Autumn.

"During this April, we experienced a really large number of
geomagnetically disturbed days and mostly low MUF values. The calm
and improvement occurred only in the last decade of April, when we
witnessed all six geomagnetically quiet days of the whole April.

"Going forward, although we do not expect a major increase in solar
activity for the time being, it will not be important during the
Northern Hemisphere ionospheric Summer. Solar activity will more or
less remain at the current level, the geomagnetic field will be
calmer compared to the past weeks - and the situation in the
ionosphere will be more favourable."
ÿ
Solar wind parameters remained slightly enhanced due to waning
positive polarity of the Coronal Hole High-Speed Stream (CH HSS)
influences. A return to a mostly ambient-like state is expected for
May 1, but by May 2, an enhancement in solar wind parameters is
likely with the arrival of a recurrent, negative polarity CH HSS.

Unsettled to active levels will likely persist into May 4 as an
additional negative polarity CH HSS moves into place.

Geomagnetic field activity is likely to reach G1 (Minor) storm
levels on May 5 and 6 due to negative polarity CH HSS influences,
and again on May 18 due to positive polarity CH HSS influences.

Periods of active conditions are likely on May 07 to 10, and on May
16 and 17 in response to CH HSS influences. Quiet and quiet to
unsettled levels are expected to prevail throughout the remainder of
the period.

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 3 to 9 is 10, 8, 18, 18, 15,
15, and 15, with a mean of 14.1.ÿ Predicted Planetary K Index is 3,
3, 5, 5, 4, 4, and 4, with a mean of 4.ÿ Predicted 10.7 centimeter
flux is 140, 140, 150, 160, 160, 165, and 165, with a mean of 154.3.

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

05/09/2025

The Solar Geophysical Activity Report and Forecast from the
USAF/NOAA indicates that solar activity has been at low levels for
the past 24 hours.

There are currently four numbered sunspot regions on the solar disk.
Solar activity is expected to be low with a chance for M-class
flares on May 10 and 11.

A simultaneous filament eruption produced a narrow Coronal Mass
Ejection (CME) signature that was first observed on May 6, and an
additional slower filament eruption was also observed. Analysis of
the events is ongoing and there was no significant growth or decay
observed in the spotted regions on the visible Sun.

The geomagnetic field is likely to experience periods of active
conditions on May 10 and 11 due to continued Coronal Hole High-Speed
Stream influences (CH HSS).

Geomagnetic field activity is likely to reach G1 (Minor) storm
levels on May 18, and May 29 to 31 due to negative polarity coronal
hole influences. Periods of active conditions are likely on May 16
and 17, and on May 19 to 21 in response to CH HSS influences.

On Spaceweather.com[1] for May 9, there is a video of a "Solar Tornado" occurring on the Sun's surface.
ÿ
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, May 8, 2025, from F. K. Janda, OK1HH:

"Although we were expecting more activity in the relatively large
sunspot group AR4079 that crossed the central meridian on May 4, it
did not happen. Indeed, its magnetic configuration did not promise
it. Instead, a sufficiently fast and proton - and especially
free-electron-rich solar wind blew from the edges of the coronal
holes, which for most of the past days since the beginning of May
caused not only increased geomagnetic activity, but also increased
attenuation and scattering of radio waves in the ionosphere.

"Only a slight improvement in the situation can be predicted. In a
few days, the only one major active region that we know about thanks
to helioseismology should appear on the eastern limb of the solar
disk. Again, it is likely to be the only one in the disk, while the
small number of remaining ones will more or less not contribute to
the overall level of solar activity.

"It remains the case that solar activity is likely to shift from the
southern hemisphere to the northern hemisphere this year, but this
will probably not yet happen in May."

The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at: https://www.youtube.com/watch?v=XZ7C6ja3ZmE[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 May 10 to 16 is 12, 10, 5, 5, 5,
5, and 12, with a mean of 7.7.ÿ The Predicted Planetary K Index for
the same period is 4, 3, 2, 2, 2, 2, and 4, with a mean of 2.7.
Predicted 10.7 centimeter flux is 165, 165, 160, 155, 155, 155, and
155, with a mean of 158.6.


[1]
[2] https://www.youtube.com/watch?v=XZ7C6ja3ZmE
[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

05/23/2025

Solar activity ranged from low to high.ÿ Region 4087 produced the strongest event of the period, an impulsive R3 flare on May 14 at 0825 UTC near the NE limb.ÿ The region also produced R2 flares at 0325 and 1119 UTC.ÿ Finally, three R1 events were produced by the region on May 14 and 15.ÿ Region 4086 also produced an R3 event, with a flare observed on May 13 at 1538 UTC.

No proton events were observed at geosynchronous orbit.ÿ However, a weak enhancement, which peaked below the S1 threshold, was observed on May 13 following the R3 event from Region 4086.

Geomagnetic field activity was at quiet levels on May 12 and 13. Late on May 16, enhancements in solar wind parameters, associated with the onset of a positive polarity CH HSS and possible influence from the southern periphery of the CME that left the Sun on May 12, increased activity to active levels.

Forecast of Solar and Geomagnetic Activity May 19 - June 14 2025:

Solar activity is expected to be at low levels, with a chance for R1-R2 (minor-moderate) events, over the outlook period.

No proton events are expected at geosynchronous orbit.

The remainder of the outlook period is expected to be at normal to moderate levels.

Geomagnetic field activity is likely to be elevated above quiet levels for most of the next 27 days due to multiple, recurrent, coronal hole features.ÿ G2 (moderate) conditions are likely on May 29 and June 13; G1 (minor) conditions likely on May 19, May 28, and June 14; active conditions are likely on May 30 - June 01, and June 10; unsettled levels are likely on May 20-23, May 27, June 02-07, and June 11-12.ÿ Quiet conditions are expected for the few remaining days of the outlook period.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere - May 22, 2025, from F. K. Janda, OK1HH.

Compared to previous months, there was a significant decrease in solar activity in May.ÿ For example, on May 2, there were only two groups of spots on the entire solar disk observed.ÿ After that, spot activity in the northern half of the solar disk increased slightly, but solar flux dropped significantly during the second third of the month.ÿ Additionally, a large coronal hole appeared in the southern hemisphere of the sun.ÿ Although this coronal hole was observed during previous rotations in March and April, it is much larger this time.

Consistent with this observation, after geomagnetic activity quieted down at the end of April, we experienced several days of strong geomagnetic disturbances in the first third of May.ÿ Starting in the second third of May, the solar flux dropped significantly, reaching values not seen since October 2024.

The combination of low solar activity and high geomagnetic activity resulted in a significant deterioration of ionospheric shortwave propagation conditions, manifested by a drop in the critical frequencies of the F2 layer and an increase in attenuation and scattering.ÿ This occurred especially on May 7-12 and May 14-18, and is likely to continue in the coming days.

The latest attempts to forecast further developments suggest that conditions should improve by the end of May.ÿ The summer ionosphere of the northern hemisphere of Earth is characterized by lower maximal frequencies and higher lows, not counting the sporadic layer E surprises.

The Predicted Planetary A Index for May 24 to 30 is 6, 5, 5, 8, 25, 30, and 20, with a mean of 14.1.ÿ The Predicted Planetary K Index is 2, 2, 2, 3, 5, 6, and 4, with a mean of 3.4.ÿ 10.7 centimeter flux is 120, 120, 120, 130, 135, 135, and 140, with a mean of 128.5. 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] ÿ. Information and tutorials on propagation can be found at, http://k9la.us/[4] .

Also, check: ÿ

"Understanding Solar Indices" from September 2002 QST:

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

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

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þ Synchronet þ Whiskey Lover's Amateur Radio BBS