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The K7RA Solar Update

This past reporting week (June 16-22) began with a bang, when the daily sunspot number was 159. But sunspot numbers declined every day to finally reach 80 on June 22.

One new sunspot group emerged on June 15, another on June 16, one more on June 18, and another on June 21.

Average daily sunspot number over the week was 124.6, up substantially from 74.3 the previous seven days.

Average daily solar flux rose from 123.9 to 140.5.

Average daily planetary A index rose from 9.7 to 11.4, and the middle latitude numbers increased one point to 11.9

It was great to see the Sun covered with spots on Spaceweather.com. Use the Archives feature toward the upper right, and you can see the

daily solar images on the left side of the page for any date in the past. I particularly appreciated the image of June 17, our Sun blanketed with sunspots!

Unfortunately, a California wildfire cut off power to the Solar Dynamics Observatory Data Center at Stanford University, so solar images are not being provided, according to Spaceweather.com.

ARRL Field Day is this weekend. What is the outlook?

The latest from US Air Force forecasters Housseal and King at the USAF 557th Weather Wing shows predicted solar flux at 120, 115 and 110 on June 24-26, and Planetary A index of 8, 12 and 15. Field Day is actually on June 25-26, but it is useful to see the prediction for Friday. The planetary A index shoes a moderate but increasing geomagnetic instability.

Newsweek reported a recent sunspot:

https://bit.ly/3xNdZiB

The latest (Thursday night) forecast from USAF shows solar flux at 120 and 115 on June 24-25, 110 on June 26-27, 100 on June 28-29, 105 on June 30, 100 on July 1-2, then 105, 110, 115, 120 and 125 on July 3-7, 130 on July 8-9, 135 on July 10, 140 on July 11-16, then 138, 134, 125 and 121 on July 17-20, then 114, 118 and 105 on July 21-23, 100 on July 24-29, then 105, 110, 115 and 120 on July 30 through August 2.

The planetary A index prediction is 8, 12, and 15 on June 24-26, 5 on June 27 to July 7, then 8, 8, 12 and 8 on July 8-11, 5 on July 12-13, 12 on July 14-16, 10 on July 17, 5 on July 18-19, then 12, 18, 12 and 10 on July 20-23, then 5 on July 24 through August 3, and 8 on August 4-5.

F.K. Janda, OK1HH wrote:

“The distribution of active areas on the Sun according to heliographic latitudes has changed relatively little during the last three solar rotations, therefore the predictions of the overall solar activity level were quite reliable.

“The parameters of the solar wind, measured around the Earth, and the activity of the geomagnetic field had a similar course.

“The highest usable frequencies of the ionospheric layer F2 (MUF) were increased on June 19-20. The sporadic-E layer played the most important role in the shortwave propagation on June 16-19.”

The latest space weather video from Dr. Tamitha Skov, WX6SWW:

A story about how “We can’t reliably predict solar cycles” can be found at:

https://bit.ly/3NiMbbx

I have no idea what prompted an incredible series of news stories late Thursday. Was it a slow news day? Perhaps an indication of a respite from national tragedies?

The following websites contain stories about our Sun, and the emergence of a big spot. Interesting because on Thursday the sunspot number declined to 69 from 80 the day before, and much lower compared to the 124.6 average for the previous seven days:

https://bit.ly/3zZ30VU
https://bit.ly/3ODJiTP
https://bit.ly/3OEDgCA
https://bit.ly/3bdRWtI
https://bit.ly/39R3SBu
https://bit.ly/3nf1B6c
https://bit.ly/3NieXsZ
https://bit.ly/3nf1QhC

https://bit.ly/3HOJOMC
https://bit.ly/3yfrIA8
https://bit.ly/3Ngyiun
https://bit.ly/3QMSw1O
https://bit.ly/3OjuY38
https://bit.ly/3yiUY9q
https://bit.ly/3HNMMAO
https://bit.ly/3tXVlDo
https://bit.ly/3HOhvhe

Massive sunspot glares at the Earth


https://bit.ly/3Ngzyh5
https://bit.ly/3yhj2cH
https://bit.ly/3QKwcGb

If 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 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/ .

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

Sunspot numbers for June 16 through 22, 2022 were 159, 152, 145, 120, 112, 104, and 80, with a mean of 124.6. 10.7 cm flux was 146.7, 148.9, 140.2, 143.6, 136.5, 138.8, and 128.7, with a mean of 140.5. Estimated planetary A indices were 12, 13, 14, 12, 10, 8, and 11, with a mean of 11.4. Middle latitude A index was 14, 14, 15, 10, 10, 10, and 10, with a mean of 11.9.

https://www.arrl.org/

 

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