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/3IQBLixDr. Tamitha Skov, WX6SWW has more of her continuing space weather course:
https://youtu.be/T8di-D1s-40I 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/ffmaIf 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 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.
ARRL
