Strong solar activity continues, with worldwide propagation on 10
and 12 meters quite commonplace.

Predicted solar flux is 255, 250, 210, 200, and 195 on December 30,
2024 through January 3, 2025, 190 on January 4-5, 170 on January 6,
160 on January 7-8, then 165, 170 and 165 on January 9-11, 170 on
January 12-13, 175 on January 14-15, 180 on January 16, 185 on
January 17-18, 200 on January 19-23, 185 on January 24-26, 175 on
January 27, and 180 on January 28-30, 2025.

Predicted planetary A index is 8, 50, 20 and 8 on December 30, 2024
through January 2, 2025, 5 on January 3-4, 8 on January 5-6, 5 on
January 7-9, then 12, 10 and 8 on January 10-12, 5 on January 13-15,
then 8, 10 and 10 on January 16-18, 8 on January 19-23, and 5 on
January 24-31.

The latest from F. K. Janda, OK1HH:

"A cooling water pipe burst in the server room of the Joint Science
Operations Center (JSOC) at the Solar Dynamics Observatory (SDO) in
California on 26 November 2024. Since then, data from the
Helioseismic and Magnetic Imager (HMI) and Atmospheric Imaging Array
(AIA) instruments have been unavailable.

"On the popular website https://www.solarham.com/ on the bottom
left, we usually find information on activity on the far side of the
Sun (at https://www.solarham.com/farside.htm) that would be needed
to predict developments around the Christmas season, for example.
This is because we were expecting the rise of active regions on the
Sun that were very active during the last solar revolution and whose
high activity we know about thanks to CMEs and the influx of protons
from flares on the Sun's far side.

"As expected, active regions on the Sun did appear and they were not
alone. Moderate solar flares are the order of the day, while we have
been expecting a geomagnetic disturbance during the Christmas
holidays since after the CME registration. But the particle clouds
missed the Earth, the disturbance did not take place, and
ionospheric shortwave propagation conditions remained above average.

"But even better propagation conditions are likely to await us next
year. The high solar activity in October this year was probably not
yet the peak of the 25th cycle - that is yet to come!"

From Space.Com, "The Sun in 2025: How the solar cycle will shape our
year ahead":

https://bit.ly/3DA4N7L

The latest report from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/qPI4_otUAME

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:

https://bit.ly/3Rc8Njt

"Understanding Solar Indices" from September 2002 QST.

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

Sunspot numbers for December 19 through 25, 2024 were 96, 148, 152,
176, 199, 219, and 218 with a mean of 172.6. 10.7 cm flux was 175,
184, 201.2, 223.3, 238.3, 258.5, and 252.7 with a mean of 219.
Planetary A index was 11, 13, 16, 14, 12, 12, and 5 with an average
of 11.9. Middle latitude A Index was 9, 10, 13, 15, 11, 9, and 5,
with a mean of 10.3.