SB PROP @ ARL $ARLP048
ARLP048 Propagation de K7RA

ZCZC AP48
QST de W1AW
Propagation Forecast Bulletin 48 ARLP048

From Tad Cook, K7RA

Seattle, WA December 1, 2023
To all radio amateurs

SB PROP ARL ARLP048
ARLP048 Propagation de K7RA

"GEOMAGNETIC DISTURBANCE WARNING 23/74 ISSUED AT 2321UT/29 NOVEMBER
2023 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

"Several CMEs are expected to impact Earth over 30 Nov and 01 Dec.
Two CMEs were observed on 27 Nov that were expected to arrive on 30
Nov, followed shortly by a very mild glancing blow from a third.

"One or possibly two halo CMEs were observed on 29 Nov which are
Earth directed. It is likely all or some of these CMEs will combine
on their trajectory toward Earth, making it difficult to pinpoint an
exact arrival time, however G3-G4 geomagnetic conditions are
possible over this period."

Over the past reporting week, ten new sunspot groups appeared.
Three on November 23, one each day on November 24 to 26, another on
November 28 and three more on November 29.

Solar numbers increased, with average daily sunspot number rising
dramatically from 83.3 to 165.9, doubling the previous week's
number.

Average daily solar flux rose from 146 to 181.5.

Geomagnetic numbers rose only slightly, with planetary A index
changing from 10.1 to 11.6, and middle latitude numbers from 7.3 to
7.6.

Predicted solar flux is 166 and 162 on December 1 and 2, 158 on
December 3 and 4, then 156, 152, 150 and 140 on December 5 to 8, 145
on December 9 and 10, 140 on December 11 to 16, 150 on December 17,
then 160 on December 18 to 28, then 165, 160 and 150 on December 29
to 31, then 145 on January 1, 2024, 140 on January 2 to 4, and 145
on January 5 and 6.

Predicted planetary A index is 54, 22 and 10 on December 1 to 3, 16
on December 4 and 5, 12 and 8 on December 6 and 7, 5 on December 8
to 11, then 10 and 8 on December 12 and 13, 5 on December 14 to 17,
then 15, 25, 8 and 5 on December 18 and 21, then 20, 10, 10, and 8
on December 22 to 25, and 5 on December 26 to 30, then 10, 16, 12
and 10 on December 31 through January 3, 2024, and 5 on January 4 to
7.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere December 1 to 7, 2023 from OK1HH.

"A week ago the CW portion of the CQ World Wide DX Contest was held.
Prior to that there were several scenarios of possible developments
during the weekend of November 25 and 26, 2023. In the end the less
likely scenario was the one that developed. This was due to a
relatively inconspicuous C-class solar flare observed on November
22.

"However, a detailed analysis of its evolution revealed that it was
preceded by a pre-eruption, which was the first signal that a CME
was likely to follow.

"Further observations from satellites and radio telescopes confirmed
the CME and measured the speed of the particle cloud. Its
rendezvous with Earth was expected on November 24, which would have
been bad enough for the contest. However, the particle cloud hit
the Earth a day later. Therefore shortwave propagation improved on
November 25 (especially in the afternoon UTC, during the positive
phase of the disturbance), whereupon an aggravation occurred on the
following day.

"The maximum of solar cycle 25 is approaching. CMEs, originating
from more energetic solar flares, or from solar plasma filament
eruptions, are hitting Earth with increasing frequency.

"For example, at the time of this writing, another geomagnetic
disturbance is expected as another CME from the eruption observed on
November 28 is expected to hit Earth on December 1 and 2.

"In the meantime, we are observing a rather large coronal hole in
the southeastern solar disk, which will deflate along its
southwestern quadrant over the next week.

"In particular, we are observing active regions to the east of it.
This neighbourhood will result in further intensification of the
solar wind and variations in geomagnetic field activity over the
next week. Its predictions do exist, but they will not be
reliable."

I noticed that OK1HH has a packet radio address. His address is:

Pmail: OK1HH@OK0NAG.BOH.CZE.EU

Cycle peak in 2024? https://bit.ly/3sXwrqi

Cycle peak in the next few months? https://bit.ly/3N7KOPG

Predicting cycle peaks. https://bit.ly/46EKxKU

A new long video from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/qiHtkXfZnQo

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.

A 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 from September, 2002 QST:

https://bit.ly/3Rc8Njt

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

Sunspot numbers for November 23 through 29, 2023 were 176, 184, 179,
169, 159, 130, and 164, with a mean of 83.3. 10.7 cm flux was
194.2, 178, 176.4, 180.2, 187.3, 183.5, and 170.6, with a mean of
146. Estimated planetary A indices were 7, 7, 38, 10, 7, 7, and 5,
with a mean of 10.1. Middle latitude A index was 4, 5, 18, 9, 2, 6,
and 9, with a mean of 7.3.
NNNN
/EX


--- MBSE BBS v1.0.8.4 (Linux-x86_64)
* Origin: American Radio Relay League (3:633/280.2@fidonet)

SB PROP @ ARL $ARLP048
ARLP048 Propagation de K7RA

ZCZC AP48
QST de W1AW
Propagation Forecast Bulletin 48 ARLP048

From Tad Cook, K7RA

Seattle, WA December 13, 2024
To all radio amateurs

SB PROP ARL ARLP048
ARLP048 Propagation de K7RA

Average daily sunpsot number plummeted to 104.4.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere
for December 12, 2024 from OK1HH:


"The high solar activity in October this year suggests that this may have
been the peak of an 11-year cycle. This is not to say that solar activity
will not continue to rise. On the contrary, it may well be that the first maximum of the cycle took place in October and that we can look forward to a second maximum. This could take place in 2025 or 2026 at the latest, but it will be followed by a decline.


"Solar activity in November was lower and December's is even lower. The expected geomagnetic disturbance, predicted for 29 November, did not take
place because the CME did not affect the Earth. However, the almost daily occurrence of moderate solar flares continued and a large flare occurred. It happened on 8 December at around 0906 UT. However, even after this eruption
no major geomagnetic disturbance followed and the changes in ionospheric shortwave propagation were rather random."


In December, the Sun is quieter, and large sunspot groups do not occur in its photosphere. The only major active regions we see are to the south of the
solar equator, and their area is about half that of those seen in November. However, the active area of AR3917 is slowly getting larger and with it the likelihood of a larger flare is increasing.


The Earth's ionosphere has been repeatedly affected in recent days by
increased concentrations of solar-origin free electrons, which, while causing
a slight rise in MUF, have been more pronounced in the ionosphere, causing scattering and hence attenuation, which has had a negative effect on the
longer shortwave bands.


More meteors are arriving at Earth these days. The swarm is called the
Geminids and most meteors should arrive about December 14. Therefore we can observe more frequent occurrences of the sporadic E layer. In addition to the occurrences of stronger signals on the longer shortwave bands, propagation through ionospheric waveguides is more frequent. The sporadic layer may not only form one of the walls of the waveguide, but also enable its termination. Which is a good chance, for example, for QRP devotees.


Predicted solar flux is 165 on December 13 to 15, 160 and 165 December 16 and 17, 160 on December 18 and 19, then 175, 185, and 190 on December 20 to 22,
185 on December 23 and 24, 180 on December 25 and 26, and 180 on December 30 through January 2, 2025.


Predicted planetary A index is 5 on January 13 and 14, 8 on January 15 and
16, 5 on January 17 to 20, then 8 on January 29.


Flare blasts South Africa: https://bit.ly/3Do6nJJ [ https://bit.ly/3Do6nJJ ]

STCE Newsletter Online version: http://www.stce.be/newsletter/newsletter.php
[ http://www.stce.be/newsletter/newsletter.php ]


PDF version: http://www.stce.be/newsletter/pdf/2024/STCEnews20241212.pdf [ http://www.stce.be/newsletter/pdf/2024/STCEnews20241212.pdf ]


Send your tips, reports, observations, questions and comments to
k7ra@rrl.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 [ http://www.arrl.org/propagation?utm_source=Informz&utm_medium=Email&utm_campaign=ARRL
] and the ARRL Technical Information Service web page at http://arrl.org/propagation-of-rf-signals [ 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 [ http://arrl.org/the-sun-the-earth-the-ionosphere ] .


An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation [ http://arrl.org/w1aw-bulletins-archive-propagation ] .


More good information and tutorials on propagation are at http://k9la.us/ [ http://k9la.us/ ] .


Check "Understanding Solar Indices" from September 2002 QST at https://bit.ly/3Rc8Njt [ https://bit.ly/3Rc8Njt ] .


Instructions for starting or ending email subscriptions to ARRL bulletins are at http://arrl.org/bulletins [ http://arrl.org/bulletins ] .


Sunspot numbers for December 5 through 11 2024 were 101, 103, 91, 103, 94,
125, 114, with a mean of 104.4. 10.7 cm flux was 174.6, 177.5, 182.5, 177.7 172.5, 171.9, and 160.5 with a mean of 170.9. Estimated planetary A indices were 4, 8, 11, 7, 6, 13, and 7, with a mean of 8. Middle latitude A Index was 3, 6, 9, 6, 6, 6, 10, and 5, with a mean of 7.3.

NNNN
/EX

ARRL(R) The National Association for Amateur Radio(R)
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--- MBSE BBS v1.0.8.4 (Linux-x86_64)
* Origin: American Radio Relay League (3:633/280.2@fidonet)