Subj : The K7RA Solar Update
To   : QST
From : ARRL de WD1CKS
Date : Sat Dec 02 2023 03:41 pm

12/01/2023

"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: [email protected][1]

Cycle peak in 2024?� https://bit.ly/3sXwrqi[2]

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

Predicting cycle peaks.� https://bit.ly/46EKxKU[4]

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

https://youtu.be/qiHtkXfZnQo[5]

Send your tips, reports, observations, questions and comments to
[email protected][6] .� 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[7] . More good information
and tutorials on propagation are at http://k9la.us/[8] Also, check this article
from September, 2002 QST:

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

Instructions for starting or ending email distribution of ARRL bulletins are at
http://arrl.org/bulletins[10]

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.


[1] mailto:[email protected]
[2] https://bit.ly/3sXwrqi
[3] https://bit.ly/3N7KOPG
[4] https://bit.ly/46EKxKU
[5] https://youtu.be/qiHtkXfZnQo
[6] mailto:[email protected]
[7] http://arrl.org/w1aw-bulletins-archive-propagation
[8] http://k9la.us/
[9] https://bit.ly/3Rc8Njt
[10] http://arrl.org/bulletins

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� Synchronet � Whiskey Lover's Amateur Radio BBS

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