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SB PROP @ ARL $ARLP051
ARLP051 Propagation de K7RA

ZCZC AP51
QST de W1AW
Propagation Forecast Bulletin 51 ARLP051

From Tad Cook, K7RA

Seattle, WA December 17, 2021
To all radio amateurs

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

Sunspots disappeared over four days, December 8-11. Average daily
sunspot numbers and solar flux hardly changed at all, with sunspots
at 24.4 during the current reporting week (December 9-15) compared
to 24.6 last week, and average daily solar flux shifting from 82.6
to 82.9.

By Wednesday solar flux rose to 102.5. But sunspots have come back
dramatically over the past few days, with the daily sunspot number
hitting 127 on Thursday, December 16. On that same day, the noon
10.7 cm solar flux reading at the Penticton observatory was 117.9
and it reached 121.5 at the 2200 UTC reading.

Geomagnetic activity was quiet. Average daily planetary A index
changed from 7.6 to 5, and average daily middle latitude A index
from 5.3 to 3.9.

One new sunspot group emerged on December 12, then two the following
day, two more on December 15 and another two on December 16.

Predicted solar flux over the next month looks very good for this
week, at 118 on December 17-21, 115 and 110 on December 22-23, 82 on
December 24-27, 80 on December 28, 78 on December 29, 2021 through
January 3, 2022, then 80 on January 4-10, 82 on January 11, and 84
on January 12-17. The predicted flux values then drop below 80 after
January 24.

Predicted planetary A index is 8 on December 17, 5 on December
18-19, then 8, 16, 12 and 8 on December 20-23, 5 on December 24-26,
then 15, 18 and 12 on December 27-29, 8 on December 30, 2021 through
January 1, 2022, 5 on January 2-8, then 8 and 5 on January 9-10,
then 12, 10, 10, and 8 on January 11-14, 5 on January 15-22, then
15, 18 and 12 on January 23-25, and 8 on January 26-28.

Unfortunately, propagation was poor last weekend during the annual
ARRL 10 Meter Contest, not surprising with no sunspots on the two
days prior to the contest and non through the weekend. On Friday
night I heard no signals (with a modest dipole antenna), so I called
CQ using CW just above 28 MHz, and worked one local station, only 8
miles away. I worked a few stations on Sunday across North America,
and heard many TEP signals from South America.

Don't miss "Understanding an Ionosonde to Understand the Ionosphere"
by propagation expert KL7AJ in January 2022 QST, currently available
online.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - December 16, 2021 from F.K. Janda, OK1HH.

"Solar activity has risen a little more and faster in recent days
than we expected. After several smaller eruptions, the probability
of an M-class solar flare increased. Although Solar Cycle 25 is
still closer to the minimum, we can expect its maximum in 3 to 4
years to be higher than usually predicted. The last rise in solar
activity is not long (in recent days only), after that a decline can
be expected again in the last week of December.

"Although most of the active areas are located south of the solar
equator and not too far from the coronal holes, we still expect only
a slight increase in geomagnetic activity at the beginning of the
third week of December.

"The Earth's ionosphere reacted significantly to the last rise of
solar radiation by the rise of MUF. However, the hitherto stable
development will be replaced by fluctuations and deformations of the
daily course - which will happen immediately, probably at the
beginning of the third week of December. This will be followed by a
relatively significant decrease in MUF, both day and night. The
decline of MUF by night will be significant if the onset of the
increase in geomagnetic activity will be up during the night."

Here is a geomagnetic activity summary from Tomas Bayer, RWC Prague
Institute of Geophysics of the ASCR, Prague Department of
Geomagnetism, Budkov observatory, preceded by a geomagnetic activity
forecast for the period December 17-23, 2021:

"Quiet: December 17-18, 22-23
Unsettled: December 18-22
Active: December 18-19
Minor storm: unlikely about December 19
Major storm: 0
Severe storm: 0

"We expect geomagnetic activity enhancement about December 18-19. We
expect an unsettled to active episode, storming defect is less
probable. Till this event, and also at the end of current forecast
period, we expect at most quiet to unsettled conditions."

Max White, M0VNG sent this from the European Space Agency:

https://bit.ly/3IQBLix

Dr. Tamitha Skov, WX6SWW has more of her continuing space weather
course:

https://youtu.be/T8di-D1s-40

I received many emails correcting the info I gave last week on the
Fred Fish Memorial Award. This sums it up best:

https://www.arrl.org/ffma

If you would like to make a comment or have a tip for our readers,
please email the author at, k7ra@arrl.net .

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals. For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere.

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good
information and tutorials on propagation are at http://k9la.us/.

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for December 9 through 15, 2021 were 0, 0, 0, 12,
40, 40, and 79, with a mean of 24.4. 10.7 cm flux was 76.7, 75.7,
76.2, 79.9, 80.6, 88.9, and 102.5, with a mean of 82.9. Estimated
planetary A indices were 3, 4, 5, 3, 6, 5, and 9, with a mean of 5.
Middle latitude A index was 2, 2, 3, 2, 6, 4, and 8, with a mean of
3.9.
NNNN
/EX

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SB PROP @ ARL $ARLP051
ARLP051 Propagation de K7RA

ZCZC AP51
QST de W1AW
Propagation Forecast Bulletin 51 ARLP051

From Tad Cook, K7RA

Seattle, WA December 23, 2022
To all radio amateurs

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

I am writing this first draft of my penultimate bulletin of 2022,
about seven hours after the start of Winter Solstice in the Northern Hemisphere, which was on Wednesday, December 21, 2022 at 2147 UTC.
It is very cold in Seattle, about 17 degrees F on the longest night
of the year.

Solar activity was down a bit from the previous week, although it
was one of those odd occasions when average daily sunspot numbers
and solar flux changed in opposite directions.

Average daily sunspot number declined from 136.9 to 124.1, while
solar flux rose from 150 to 153.8.

Two new sunspot groups emerged on December 17, one more on December
19, another on December 21, and two more on December 22.

Geomagnetic indicators were a bit lower, with average planetary A
index changing from 7.7 to 6.7, and middle latitude numbers from 6
to 5.1.

Due to missing data, I had to fudge one of the numbers, the December
16 middle latitude A index which I pegged at 7 by eyeballing trends.

Predicted solar flux appears to reach a short term peak of 160 on
January 4-7, 2023, which may repeat on the last day of January and
the first few days in February.

The forecast shows 130 on December 23-25, 135 on December 26-30,
138 on December 31, then 140, 150 and 155 on January 1-3, 2023, 160
on January 4-7, then 158, 156, 154, 154 and 152 on January 8-12, 150
on January 13-15, then 145, 130 and 120 on January 16-18, 118 on
January 19-20, then 120, 125 and 127 on January 21-23, 130 on
January 24-25, then 135, 138, 140, 150 and 155 on January 26, and
160 on January 31 through the first few days of February.

Predicted planetary A index is 8, 5 and 8 on December 23-25, 5 on
December 26-29, 10 and 12 on December 30-31, then 8, 5 and 18 on
January 1-3, 2023, 10 on January 4-5, then 8, 10 and 6 on January
6-8, 5 on January 9-14, then 12, 10 and 20 on January 15-17, then
12, 8, 5 and 18 on January 18-21, and 20 on January 22-24, then 12,
10, 12, 8 and 5 on January 25-29.

OK1HH writes:

"Over the past seven days, we observed up to seven sunspot groups on
the solar disk, three in succession had sizes and configurations
suggesting the possibility of an M-class flare.

"AR3165 fell behind the western limb on December 17, while we
observed AR3169 the same day. The largest AR3163 went over the limb
on December 22. Solar activity, both total and flare activity,
slowly decreased.

"A shock wave (probably the CME released by sunspot AR3165 last
week) hit Earth's magnetic field late on December 18, but a
geomagnetic storm did not develop, only a slight increase in
geomagnetic activity. This was repeated on December 21 and
especially the next day, when it was a recurrent disturbance,
repeated after about 27 days.

"Solar activity is likely to remain low until Christmas. The
situation may change next week, when one or more active sunspot
groups will appear on the eastern limb of the solar disk.

"Shortwave propagation was mostly above average with slightly
elevated MUF values. Diurnal variations were erratic. This pattern
will continue."

Jon, N0JK wrote:

"A strong sporadic-E opening on 50 MHz from Kansas to the Gulf Coast
Sunday December 18.

"I logged K3FM EM50, WA3GWK EM60, W5THT EM50, and N4UPX EM50 on
50.313 MHz FT8 around 1600 UTC with strong signals. My station was
100 watts and an attic dipole."

More big solar flare news:

https://bit.ly/3YHi5Wf

https://bit.ly/3PKXts4

https://bit.ly/3HXk1DW

https://bit.ly/3FPgipw

Found this interesting resource in the ARRL Letter:

https://haarp.gi.alaska.edu/diagnostic-suite

From Dr. Tony Phillips on cycles:

https://spaceweatherarchive.com/2022/12/

On Thursday using remotehamradio.com I made a 10 meter contact with
Ralph, VE3LOE. He sent me an email, which I have edited:

"About 2 years ago I was in touch with Scott McIntosh at the
National Center for Atmospheric Research in Boulder, CO, who made a minority-opinion propagation forecast for Solar Cycle 25 which
suggests much higher solar activity than what his colleagues
predict. See 'Overlapping Magnetic Activity Cycles and the Sunspot
Number: Forecasting Sunspot Cycle 25 Amplitude' (text dated October
2020).

"The latest installment, entitled 'Deciphering Solar Magnetic
Activity: The (Solar) Hale Cycle Terminator of 2021,' which is at:

"https://arxiv.org/a/mcintosh_s_1.html

"I scanned this latter paper just now. Although I am a retired
engineer from the telecom sector with a PhD in statistical traffic
analysis of pre-Internet data networks, and understand the
statistical math used in these papers, I am not a propagation
expert. However, in the last publication, Figure 10 predicts a mean
SSN just under 200, higher than other expert predictions. This
present cycle has been interesting in its statistical variability.

"I am primarily a 10m enthusiast and use this band on a daily basis,
generally in the 1300-1700 UTC timeframe when the EU openings take
place. For some of my other ham interests and operating conditions
you can visit my QRZ.com page."

K7RA notes - download this pdf:

https://arxiv.org/pdf/2209.10577.pdf

A new report from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/pU6i_2FVR2g

Send your tips, reports, observations, questions, and comments to k7ra@arrl.net.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information
Service at http://arrl.org/propagation-of-rf-signals . For an
explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good
information and tutorials on propagation are at http://k9la.us/ .

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for December 15 through 21, 2022 were 140, 108, 139,
128, 132, 119, and 103, with a mean of 124.1. 10.7 cm flux was
165.9, 163.1, 154.6, 155,6, 152.4, 146.4, and 138.7, with a mean of
153.8. Estimated planetary A indices were 5, 9, 3, 4, 11, 6, and 9,
with a mean of 6.7. Middle latitude A index was 4, 7, 2, 2, 9, 5,
and 7, with a mean of 5.1.
NNNN
/EX

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SB PROP @ ARL $ARLP051
ARLP051 Propagation de K7RA

ZCZC AP51
QST de W1AW
Propagation Forecast Bulletin 51 ARLP051

From Tad Cook, K7RA

Seattle, WA December 22, 2023
To all radio amateurs

SB PROP ARL ARLP051
ARLP051 Propagation de K7RA

The Winter Solstice, the shortest day of the year in the Northern
Hemisphere occurred at 0327 UTC on December 22. It is the start of
summer in the Southern Hemisphere.

Solar activity increased over the last reporting week (December
14-20), with eleven new sunspot groups emerging.

One new sunspot group appeared on December 15, four more on the
following day, another on December 17, three more on December 18,
and two more in December 19-20.

Average daily sunspot number rose from 110.3 to 137.4, solar flux
from 129.8 to 162.7, planetary A index 5.6 to 18.4, and middle
latitude A index from 4.6 to 13.7.

The most active day was Sunday, December 17 when the planetary A
index was 36, and Alaska's college A index was 88.

The cause was what Spaceweather.com reported as the strongest flare
of the current solar cycle, an X2.8 class, and it caused a radio
blackout.

Here is a video of the brief flash:

https://bit.ly/3RP3xCw

Spaceweather.com reported on Wednesday that another flare is coming
from sunspot group AR3529, and here is a movie they posted:

https://bit.ly/3tipAbr

Predicted solar flux is 190, 188 and 186 on December 22-24, then
182, 180, 170 and 165 on December 25-28, 145 on December 29-30, 150
on December 31, then 145, 140 and 138 on January 1-3, 2024, then 136
on January 4-5, then 140, 145 and 148 on January 6-8, 145 on January
9-12, then 150, 147, 145, 140, and 138 on January 13-17, 136 on
January 18-19, then 140, 145 and 148 on January 20-22, then 145 on
January 23-26, then 150, 145, 140 and 138 on January 27-30.

Predicted planetary A index is 5, 12 and 8 on December 22-24, 5 on
December 25-29, 8 on December 30-31, then 10 and 8 on January 1-2,
2024, 5 on January 3-7, 10 on January 8-9, 8 on January 10, 5 on
January 11-13, 15 on January 14, 12 on January 15-16, and 8 on
January 17-19, then 5 on January 20-25, and 8 on January 26-27.

Jon Jones, N0JK wrote, from Kansas:

"Some winter 6 meter Es December 18-19. N7BHC (EL15) and KD5CAF
(EL18) into EM28 for me on FT8 around 0100 UTC December 19. Earlier
stations in Colorado, Kansas, and Missouri had ZL7DX in on 6 meters
at 2200 UTC December 18."

Here is a new, long video from Dr. Tamitha Skov, WX6SWW, from
earlier this week:

https://bit.ly/3GPRYET

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - December 21, 2023 from F.K. Janda, OK1HH:

"Astronomical winter began in the Northern Hemisphere at the moment
of the Winter Solstice: December 22 at 0327 UTC. On this day is the
longest night and, of course, the shortest day. The total effect of
solar X-ray and ultraviolet radiation on the ionosphere of our
hemisphere was thus relatively the smallest of the entire year, and
the effects of changes in the solar wind were all the more
effective. This is also one of the reasons why, despite relatively
high solar activity, the shortwave propagation conditions are worse
than we would like and then we expected.

"Over the next six months, the length of the day will increase until
the Summer Solstice on June 20. Slowly at first, then faster,
fastest around the Spring Equinox on March 20. It is certain that
then the propagation conditions will be significantly better than
now. It is even possible that the maximum of the eleven-year cycle
will occur as early as next year, although it would be better for us
if it did not occur until 2025.

"Although we have not observed any particularly large sunspot groups
in recent weeks, there were always one or two active regions among
them, whose magnetic configuration allowed the development of a
medium-sized eruption, possibly even with a CME - after all we
observed several of these. The exception was the X2.8 class eruption
on December 14 at 1702 UTC, the strongest so far since the beginning
of the 25th solar cycle, or since the major disturbances in
September 2017.

"The eruption originated in AR3514, which was approaching the
western limb of the Sun. Even though it hurled a fast-moving CME
into space, it was relatively unlikely to cause strong geomagnetic
storms here on Earth. Eventually, the CME either missed Earth or hit
so weakly that it was not detected by satellite sensors.

"During the rise of the solar flux from 126 on December 12 to 195 on
December 20, with the corresponding increase in solar X-ray
radiation, shortwave propagation improved only slightly, actually
fluctuating, which was expected.

"The last geomagnetically quiet day was December 13, after which the
Earth's magnetic field was unsettled to active (more precisely:
active around last weekend). However, most days until the end of
this year should be geomagnetically quieter, while the solar flux
will remain elevated. Therefore, we can expect slightly better
propagation."

Here are a number of articles about a Big Flare:

https://bit.ly/3RQG4Rb

https://bit.ly/3RRzBpe

https://bit.ly/48tJtuH

https://bit.ly/3TAeybV

https://bit.ly/48pIpbo

https://bit.ly/488c88X

https://bit.ly/3tymsrK

https://bit.ly/3RwJzLh

https://bit.ly/3RThBuQ

https://bit.ly/3RRzzh0

An article about Radio Blackout:

https://bit.ly/3v5b5Il

Send your tips, reports, observations, questions and comments to
k7ra@arrl.net. When reporting observations, don't forget to tell us
which mode you were operating.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals . For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good
information and tutorials on propagation are at http://k9la.us/ .

Also, check this article about understanding solar indices:

https://bit.ly/3Rc8Njt

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for December 14 through 20, 2023 were 126, 130, 163,
129, 137, 144, and 133, with a mean of 137.4. 10.7 cm flux was
155.1, 144.3, 149, 154.6, 161.4, 179.3, and 195.3, with a mean of
162.7. Estimated planetary A indices were 16, 12, 14, 36, 28, 12,
and 11, with a mean of 18.4. Middle latitude A index was 13, 8, 10,
32, 16, 10, and 7, with a mean of 13.7.
NNNN
/EX

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