The K7RA Solar Update

New sunspot groups, nine in all, emerged on every day of this reporting week, July 4 to 10. One on July 4, another on July 5, two more on July 6, another each on July 7 and July 8, two more on July 9 and another on July 10.

On July 11, two more sunspot groups emerged, and the total sunspot area expanded by 13 per cent.

Despite the appearance of so many new sunspots, average daily sunspot number declined from 181.6 to 129, compared to the previous week. Average daily solar flux barely moved, changing from 175 to 176.6.

Predicted solar flux for the next month is 205 on July 12 and 13, 210 on July 14 and 15, 205 on July 16 to 18, 195 on July 19 and 20, 200 on July 21 to 25, 190 on July 26, 180 on July 27 to 29, 175 on July 30, and 170 on July 31 through August 2, then 165 on August 3 to 6, 160 on August 7 and 8, 175 on August 9, 180 on August 10 to 13, 195 on August 14 to 16, and 200 on August 17 to 21.

Predicted planetary A index is 8, 15, 18, 12 and 8 on July 12 to 16, 5 on July 17 to 20, then 10 and 8 on July 21 and 22, then 5 on July 23 to August 3, then 12, 10, and 5 on August 4 to 6, then 12, 8 and 5 on August 7 to 9, then 12, 10 and 8 on August 10 to 12, then 5 on August 13 to 15, and 10 and 8 on August 16 and 17 and 5 on August 18 and beyond.

Tamitha Skov wrote in an email on Wednesday:

We have a new big flare player rotating through the Earth-strike zone with some X-flare potential. Region 3738 has been growing rapidly over the past 24 hours, with some new spot clusters emerging right in the center of the original set. This kind of growth is highly magnetically unstable and is upping the noise on the day-side radio bands.

As of earlier today, we had already popped a couple of low-level M-class flares and now are approaching the R1-radio blackout level for a noise floor. That is quick growth! I did my best to estimate the conditions for the coming week in these 5-day Outlooks, but in the time it has taken to generate them, the region's growth has accelerated.

It looks like I will need to update the Solar Flare and Day side Radio Blackout Outlook in the above snapshot to something closer to a 60 per cent chance of M-Class flares and a 15 per cent chance of X-class flares. I will do this asap!

Other than Region 3738, we do have a pocket of fast solar wind coming that could give us a decent chance of aurora at high latitudes over the early part of the weekend. This is the only solar storm possibility for now, although we could see a new Earth-directed solar storm launch over the next few days! I will go over this possibility and the new fireworks from Region 3738 in the upcoming forecast I am shooting now.

Dr. Tamitha Skov has many videos of interest to our readers.  You can find them here:

https://www.youtube.com/c/TamithaSkov

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, July 11, 2024 from F. K. Janda, OK1HH.

In early July, a sunspot group responsible for the May 10 superstorm reappeared on the southeastern limb. By the way, this superstorm caused thousands of satellites to drop in altitude, according to a research paper just accepted by the Journal of Spacecraft and Rockets.

The aforementioned group was designated AR3664 at the time, in subsequent solar rotations AR3697, AR3723, is visible again, while in the same region are now AR3742, AR3743, and AR3745.

The most active is the rapidly growing AR3768, five times the size of the Earth. Most importantly, there is a coronal hole to the north of AR3768. Between mentioned CH and AR we can expect a source of enhanced solar wind that will very likely head towards the Earth and cause a geomagnetic disturbance on July 13 and 14. Ionospheric shortwave propagation conditions, randomly influenced by sporadic layer E in the northern hemisphere of the Earth during the summer, affected by numerous solar flares will develop, but less regularly.

Cycles 24 and 25 compared: https://bit.ly/3Y05gIM

Sunspot number calculations and the peak of the cycle: https://yhoo.it/3WjX5Wg 

Five flares: https://bit.ly/3WlwuqT

David Moore sent this about solar convection:  

https://bit.ly/3WlQCKF

Solar max: https://bit.ly/3xK36lR

New look at Maunder minima: https://bit.ly/3WgVoJh

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 July 4 through 10 2024 were 113, 111, 132, 119, 95, 143, and 190, with a mean of 129. 10.7 cm flux was 173, 165.6, 166, 171.3, 168.5, 178.2, and 213.6, with a mean of 176.6. Estimated planetary A indices were 10, 8, 3, 8, 10, 6, and 6, with a mean of 7.3. Middle latitude A Index was 10, 10, 4, 7, 11, 8, and 8, with a mean of 8.3.