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

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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

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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

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þ Synchronet þ Whiskey Lover's Amateur Radio BBS