12/05/2025

Solar activity was at low levels this past week with only C class
flares. Region 4294 remains the largest region on the disk but is
appearing to be simplifying magnetically. Region 4296, on the other
hand, gained a delta region in its intermediary region, though with
no corresponding increase in flare activity as of yet. New flux
emerged along the eastern side of Region 4298, resulting in several
C flares throughout the reporting period. Region 4299 also developed
a delta region in its primary spot but no appreciable shear was
observed. Region 4301 developed, was numbered, but was otherwise
unremarkable. No Earth directed CMEs were observed in available
coronagraph imagery.
ÿ
Isolated to occasional M class flares are expected through December
6, with a chance for X class flares, given past flare history, and
the potential of current active regions on the disk.
ÿ
The environment will likely remain enhanced due to fast solar wind
conditions through December 6.

M class flares (R1 to R2/Minor to Moderate) are likely, with slight
chance for X flares (R3 Strong or greater), through 12 Dec due
primarily to the flare potential of Region 4294.

Geomagnetic activity is likely to reach active levels on December 3
and 6, and G1 (Minor) storm levels on December 4 and 5, driven by
influences from a negative polarity CH HSS.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, December 4, 2025, by F. K. Janda, OK1HH:

The significant increase in solar activity since the beginning of
December has finally confirmed the original assumption that the
current 25th eleven year solar cycle will have two peaks. The first
occurred last October, while we have been eagerly awaiting the
second this year (especially in the fall). The increase in activity
at the end of this summer started promisingly, but it was only the
first of several. It was only after the large solar flare on
November 11, 2025, which was the largest since October 3, 2024, that
it was possible to estimate that the second maximum was approaching.

High solar activity period can be expected during the first half of
December, while it is a bit of a shame that it did not occur a week
or two earlier. This would have been particularly appreciated by
shortwave radio amateurs, as the telegraph part of the largest
competition, the CW WW DX Contest,ÿ traditionally takes place
during the last weekend of November.

Although the current parameters of high speed solar wind do not
create exactly the structure of the Earth's ionosphere that we would
like, at least the highest usable frequencies allow connections to
be established on all shortwave bands. During December, we are
likely to experience another increase in solar activity in the last
third of the month, preceded by several days of increased
geomagnetic activity.

The latest video report from Dr. Tamitha Skov, WX1SWW, can be found
on Youtube.

The Predicted Planetary A Index for December 6 to 12 is 12, 10, 8,
5, 5, 5, 8 with a mean of 7.5. Predicted Planetary K Index is 4, 3,
3, 2, 2, 2, and 3, with a mean of 2.7. 10.7 centimeter flux is 190,
190, 190, 190, 185, 180, and 180, with a mean of 186.4.
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.
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

12/12/2025

Solar activity reached high levels this past week when Region 4299
produced an M1.1 (R1/Minor) flare on December 6. Shortly after, the
region produced an M8.1/2b (R3/Strong) flare, also on December 6.
Associated with the M8.1 flare was a 1,100 SFU Tenflare, a 1,143
km/s Type II sweep and a Type IV sweep. (A "sweep" is a solar radio
burst that sweeps through the RF spectrum as the energy moves
outward from the Sun.)

Some development was observed around the leader spot of Region 4299,
while slight decay was noted among the trailer spots. Regions 4296
and 4294 remained the largest of the visible disk but have only
produced C-class activity in the past 24 hours. Only minor changes
were observed among the other numbered active regions and activity
is now moderate.
ÿ
Coronal mass ejection (CME) activity was observed from both M-class
flares. A slow, Earth-directed CME was observed from the M1.1 and a
faster, full-halo, Earth-directed CME was observed from the M8.1
flare. According to Spaceweather.com[1], it touched off a G2 (moderate) geomagnetic storm on December 10.
ÿ
Solar wind parameters reflected a disturbed near-Earth environment
throughout the reporting period. Solar wind speeds showed little
reaction to the magnetic transient, averaging 375 km/s throughout
the reporting period. The phi angle was oriented towards-the-Sun
(negative) for the majority of the reporting period, then slowly
rotated around to away-from-the-Sun (positive) 1.5 hours after the
arrival of the transient.
ÿ
The electron flux is expected to become elevated through December 14
as a coronal hole high speed stream (CH HSS) originating from the
negative polarity coronal hole in the northern hemisphere becomes
geoeffective. The flux is likely to surpass the 1,000 pfu threshold
during the diurnal maxima.

As complex regions in the western hemisphere move beyond the limb,
chances for the proton flux to become elevated decrease. There is a
10% chance for an S1 (Minor) radiation storming event on December
12, with chances decreasing to 1% by December 14.

Spaceweather.com[2] for December 12 reports on the Geminids Meteor
Showers peaking this upcoming weekend.

A story on the Meteor Scatter QSO Party can be found on the ARRL
website at, http://arrl.org/news/operators-monitors-wanted-for-meteor-scatter-qso-party-dec ember-12-13[3] .

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, December 4, 2025, by F. K. Janda, OK1HH:

"On December 1, an active sunspot group emerged on the southeastern
limb of the solar disk, as expected. During the last solar rotation,
it was designated AR4274. Astronomers renamed it now as AR4294,
while produced the first in a series of energetically significant
flares observed during the first third of December. In addition,
AR4296 began to grow right next to it, and together they began to
resemble the so-called Carrington region of 1859. However, the
growth of both regions slowed down, but moderately powerful
eruptions continued to occur in them, surprisingly contributed to by
the relatively small group AR4299 in the north of the solar disk.

"Another energetically significant solar flare on December 8 came as
a surprise. Given the speed of the ejected particles, the CME was
expected to hit Earth on December 9. However, they apparently
traveled to Earth along a longer path and arrived on December 10.
Therefore, they encountered a slow and expected stream of particles
that last hit Earth on November 12. The result of the encounter
between the slow and fast particle streams was a so-called reverse
shock at around 20:00 UT on December 10, which triggered a G2-class
geomagnetic storm. However, these storms are usually short-lived
and, apart from unusual, irregular (and interesting) developments,
they did not have any significant consequences.

"Solar activity remains high, and the state of the ionosphere
reflects this. However, the fact that the conditions for shortwave
propagation are different from previous cycles is another story.
Every eleven-year cycle is different."

The latest video from Dr. Tamitha Skov, WX6SWW, can be found on
YouTube at, https://www.youtube.com/watch?v=zsh1fLbrUjk[4] .

The Predicted Planetary A Index for December 13 to 19 is 12, 12, 8,
5, 8, 10, and 8, with a mean of 9.ÿ Predicted Planetary K Index is
4, 4, 3, 2, 3, 3, and 3, with a mean of 3.1.ÿ 10.7-centimeter flux
is 140, 130, 130, 135, 135, 140, and 140, with a mean of 135.8.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation[5] and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals[6]. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere[7] . Information and
tutorials on propagation can be found at, http://k9la.us/[8] .

Also, check this:

https://bit.ly/3Rc8Njt[9]

"Understanding Solar Indices" from September 2002 QST.

ÿ


[1] http://Spaceweather.com
[2] http://Spaceweather.com
[3] http://arrl.org/news/operators-monitors-wanted-for-meteor-scatter-qso-party-december-12-13
[4] https://www.youtube.com/watch?v=zsh1fLbrUjk
[5] http://www.arrl.org/propagation
[6] http://arrl.org/propagation-of-rf-signals
[7] http://arrl.org/the-sun-the-earth-the-ionosphere
[8] http://k9la.us/
[9] https://bit.ly/3Rc8Njt
---
þ Synchronet þ Whiskey Lover's Amateur Radio BBS