The recent reporting week, December 21-27, saw counter-intuitive solar numbers, with solar flux rising but sunspot numbers in decline. This happens from time to time.

Average daily sunspot numbers declined from 137.4 to 114.4. Only three new sunspot groups emerged, two on December 22, and one on December 27. On Thursday, December 28 one more sunspot emerged and the sunspot number increased from 78 to 83.

Average daily solar flux rose from 162.7 to 172.6.

Predicted solar flux over the next month is 145 on December 29-30, 140 on December 31 to January 1, 2024, 135 on January 2-4, 150 on January 5-7, 155 on January 8-11, then 150, 155, 160, 170 and 175 on January 12-16, 180 on January 17-21, then 170, 165, 162, 155 and 145 on January 22-26, then 140 on January 27-30, and 150 on January 31 to February 3.

Predicted planetary A index is 5, 10, 8, 16, and 8 on December 29 through January 2, 2024, then 5 on January 3-7, then 10, 10 and 8 on  January 8-10, then 5 on January 11-25, then 12, 10, 10 and 8 on January 26-29, and 5 on January 30 through February 3.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere, December 28, 2023 from F. K. Janda, OK1HH.

“There are active regions on the Sun that may not even be large, but whose magnetic configuration points to the possibility of solar flares, up to moderately important ones. CMEs are no exception, but they may not hit the Earth at all.

“On December 24, three moderate-importance flares were observed. At least one of them produced a CME. Based on measurements of its velocity, the collision with Earth was predicted to December 27. However, nothing happened, and despite the extension of the prediction of the onset of the disturbance by a day, calm continued on 28 December.

“For many days now there has been such a large active region on the Sun’s far side that it is affecting the vibration of the entire Sun. In addition, it has been observed by NASA’s Mars Perseverance rover camera. While it is primarily designed to see if there is dust in the air, it can see large sunspots and, most importantly, the sun’s far side is now visible from Mars.

“So we await the return of AR 3514, which will rise in the northeastern solar disk shortly after the New Year. It will be a significant contributor to the further rise in solar activity in the days ahead. Furthermore, longer term forecasts are calling for high solar activity in the second half of January. So perhaps we will finally see an improvement in shortwave conditions.”

Don’t forget ARRL Straight Key Night is this weekend, for all of New Years Day (UTC), so that starts at 4:00 PM Sunday here on the Left Coast where I live. Operate CW in a casual event using your straight key or semi-automatic bug.

Recent activity: https://bit.ly/3vhqLIE

Sun as revolving field motor: https://bit.ly/41CbEFA

Aurora: https://www.dailymotion.com/video/x8qwdc5

2023 solar activity:

http://tinyurl.com/55x96tfd   https://bit.ly/3RYngj1

Cosmic spectacle: https://bit.ly/41C8kdR

Larger storms: https://bit.ly/3RDl4fB

Tamitha Skov’s latest report: https://youtu.be/-xt-qMPQWwE

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: https://bit.ly/3Rc8Njt

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

Sunspot numbers for December 21 through 27, 2023 were 138, 157, 123, 113, 98, 94, and 78, with a mean of 114.4. 10.7 cm flux was 193.6, 186.7, 174.2, 183.4, 166.7, 154.2, and 149.4, with a mean of 172.6. Estimated planetary A indices were 5, 4, 7, 9, 4, 5, and 4, with a mean of 5.4. Middle latitude A index was 3, 3, 5, 7, 2, 4, and 4, with a mean of 4.

There will be no informational net on Sunday December 24, 2023 and Dec 31, 2023 due to the holidays. See you again on Jan. 7 2024.

The winter solstice (the shortest day of the year in the Northern Hemisphere) will occur at 0327 UTC on December 22, 2023. This also marks the start of the summer solstice in the Southern Hemisphere.

Solar activity increased over the last reporting week of December 14 – 20 with 11 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 on December 19 – 20.

The average daily sunspot number rose from 110.3 to 137.4, and the solar flux rose from 129.8 to 162.7. The planetary A index increased from 5.6 to 18.4, and the middle latitude A index grew 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. Spaceweather.com reported the cause was from the strongest flare of the current solar cycle, an X2.8 class, and it caused a radio blackout.

You can watch a video of the brief flash at https://bit.ly/3RP3xCw.

Spaceweather.com also reported that another flare is coming from sunspot group AR3529. Watch the movie they supplied at https://bit.ly/3tipAbr.

Predicted solar flux is 190, 188, and 186 on December 21 – 23; 182, 180, 170, and 165 on December 24 – 27; 145 on December 28 – 30; 150 on December 31; 145, 140, and 138 on January 1 – 3, 2024; 136 on January 4 – 5; 140, 145, and 148 on January 6 – 8; 145 on January 9 – 12, and 150, 147, 145, and 140 on January 13 – 16.

Predicted planetary A index is 10, 5, 12, and 8 on December 21 – 24; 5 on December 25 – 29; 8 on December 30 – 31; 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.

Watch Dr. Tamitha Skov’s, WX6SWW, new video from earlier this week at https://bit.ly/3GPRYET.

Read about big solar flares at https://bit.ly/3RQG4Rb, https://bit.ly/3RRzBpe, and https://bit.ly/48tJtuH.

Read about a temporary radio-signal blackout at https://bit.ly/3v5b5Il.

Sunspot numbers for December 14 – 20, were 126, 130, 163, 129, 137, 144, and 133, with a mean of 137.4. The 10.7-centimeter 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. The middle latitude A index was 13, 8, 10, 32, 16, 10, and 7, with a mean of 13.7.

Solar activity declined this week. The average daily sunspot number dropped from 121.1 to 110.3, and the average daily solar flux decreased from 146.5 to 129.8.

Six new sunspot groups appeared this week. The first two appeared on December 8, another two appeared on December 11 and 12, and two more appeared on December 13.

Geomagnetic conditions were quieter, with the planetary A index dropping from 14.1 to 5.6, and the middle latitude numbers decreasing from 7.3 to 4.6.

Predicted solar flux shows some expected improvement, with values peaking at 160 on December 20 – 21 and 155 on January 23.

Predicted solar flux is 135 on December 14 – 16; 145, 150, and 155 on December 17 – 19; 160 on December 20 – 21, and then it drops back to 135 on December 22. It will be 140 on December 23 – 24; 150 on December 25 – 26; 155, 150, and 145 on December 27 – 29; 140 on December 30 through January 2, 2024, and 135 on January 3 – 5.

Predicted planetary A index is 8, 18, and 22 on December 14 – 16; 12 on December 17 – 18; 18, 8, 8, 20, and 10 on December 19 – 23; 5 on December 24 – 29; 8 on December 30 – 31; 10 and 8 on January 1 – 2, 2024, and 5 on January 3 – 6.

Reader David Moore shared an article about agencies collaborating on space weather projects. You can read it at https://bit.ly/46ZKDNF.

On Wednesday morning, Spaceweather.com announced:

“The best meteor shower of the year peak[ed] on December 13 – 14 with no moon to spoil the show. Rural observers could see hundreds of Geminid meteors and more than a few fireballs.”

Did you know that India has a solar observatory in space? Read about it at https://bit.ly/3GGecsH.

Watch Tamitha Skov’s new video from this week about the solar storm forecast at https://youtu.be/64CTIrWBGTc.

A couple of interesting QRZ.com pages to check out are KS7ROH‘s for his astrophotography and other projects, and W6BSD‘s for links to his propagation pages.

Sunspot numbers for December 7 through 13, 2023, were 121, 125, 125, 120, 87, 80, and 114, with a mean of 110.3. The 10.7-centimeter flux was 134.6, 132.6, 127.9, 126.6, 125.9, 126.2, and 134.8, with a mean of 129.8. Estimated planetary A indices were 5, 5, 3, 4, 3, 10, and 8, with a mean of 5.6. Middle latitude A index was 4, 4, 2, 4, 3, 8, and 7, with a mean of 4.6.

Six new sunspot groups emerged over this reporting week, November 30 to December 6, 2023.

Using the previous week’s bulletin as a template, last week’s averages were not updated, although all the correct data was there. This week’s bulletin includes the updated averages from last week.

Instead of 83.3 being the average daily sunspot number, it was actually 165.9, which dropped this week to 121.1.

Instead of an average daily solar flux of 146, it was actually 181.5, which declined this week to 146.5.

Instead of the average daily planetary A index of 10.1, it was actually 11.6, which rose this week to 17.1. Instead of the average middle latitude A index of 7.3, it was 9, which rose this week to 11.4.

Predicted solar flux is 130, 135, 135, and 140 on December 7 – 10; 130 on December 11 – 13; 140 on December 14 – 16; 150 on December 17; 160 on December 18 – 26; 155, 150, 145, and 140 on December 27 – 30; 136, 134, and 130 on December 31 through January 2, 2024, and 132 on January 3 – 5.

Predicted planetary A index is 8 on December 7; 5 on December 8 – 10; 8 on December 11 – 12; 5 on December 13 – 17; 15, 25, 8, 5, 20, and 10 on December 18 – 23; 5 on December 24 – 30; 25, 10, and 8 on December 31 through January 2, 2024, and 5 on January 3 – 6.

Read about a big hole in the sun at https://bit.ly/41adYDC and the sun’s new active region at https://bit.ly/3RxtCWG.

Don’t forget, the ARRL 10-Meter Contest is this weekend. Visit https://www.arrl.org/10-meter to learn more. Sunspot numbers for November 30 through December 6, 2023, were 138, 140, 92, 107, 113, 133, and 125, with a mean of 121.1. The 10.7-centimeter flux was 166.5, 162, 148.2, 139.2, 137.8, 141.6, and 129.9, with a mean of 146.5. Estimated planetary A indices were 5, 56, 14, 11, 9, 15, and 10, with a mean of 17.1. Middle latitude A index was 4, 30, 11, 10, 9, 9, and 7, with a mean of 7.3.