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Sunspot numbers and solar flux increased this week (September 29 through October 5), as expected with the solar cycle progressing toward a probable peak in summer 2025.
Average daily sunspot number increased from 105.1 to 111.4, and average daily 10.7 cm solar flux from 138.4 to 149.2.
Compare this to a year ago, when average daily sunspot number was just 59.4 and solar flux was 89.8.
This last week there were two new sunspot groups on September 30, one more on October 1, three on October 3, and one more on Thursday, October 6.
I have been noticing improved 10 meter propagation with openings lasting all day, now that the autumnal equinox passed two weeks ago and with higher sunspot numbers.
Predicted solar flux is 156 on October 7, 154 on October 8 and 9, then 152 and 150 on October 10 and 11, 148 on October 12 to 14, 130 on October 15, 135 on October 16 and 17, 140 on October 18, 145 on October 19 to 21, 150 on October 22 and 23, then 145, 140 and 135 on October 24 to 26, 145 on October 27 and 28, 150 on October 29, 155 on October 30 and 31, 145 on November 1, 135 on November 2 to 4, 130 on November 5 and 6, 135 on November 7, 140 on November 8 and 9, 130 on November 10 and 11 and 135 on November 12 and 13.
Predicted planetary A index is 14, 10, 12 and 8 on October 7 to 10, 5 on October 11 to 13, 8 on October 14, 10 on October 15 and 16, then 8 on October 17 to 19, 12 on October 20 and 21, 8 on October 22 to 29, then 20, 12 and 10 on October 30 through November 1, then 8 on November 2 to 10 and 10 on November 11 and 12.
On October 2, Spaceweather.com announced "A Big Dangerous Sunspot", AR3112, one of the biggest in years had just rotated over the sun's eastern horizon. They predict this could produce two weeks of high solar activity.
F. K. Janda, OK1HH reports, "A week ago it seemed that following conditions would be calmer. This assumption was shattered after AR3112 sunspot group, with its complex magnetic structure, began to appear on the northeastern edge of the solar disk.
Prior to that, we expected the earth to be hit by a fast solar wind from a CME that left the sun on September 28, but only a slight increase in geomagnetic activity followed on September 28 and October 2.
However, we did get an X1 flare on October 2 at 2025 UTC, which ironically did not originate from the large dangerous AR3112 group, but from the smaller and apparently less threatening AR3110 active region. It amplified the SWF (shortwave fade out) in the Pacific and parts of North America. Apparently, it blasted a CME into space.
This development was followed by the introduction of AR3112 with over a dozen dark nuclei scattered over 130,000 km of the solar disk.
It remained the case that most of the incoming CMEs were hurled into space by the AR3110 group of spots, in which we observed a series of strong flares (M5.9, M8.7, X1) over the weekend.
As a result, several CMEs headed towards Earth.
However, the geomagnetic field was only steady to active in the following days.
Not only does the chance for energetic flares in the AR3112 region persist, but on October 4, a 200,000 km long magnetic filament erupted in the southern hemisphere of the Sun. The plasma clouds are not heading directly towards Earth, but some could hit on 8 October."
Big filament.
The latest from WX6SWW, Space Weather Woman Dr. Tamitha Skov.
Send your tips, reports, observations, questions and comments to 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/ .
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Sunspot numbers for September 29 through October 5, 2022 were 56, 74, 100, 102, 144, 153, and 151, with a mean of 111.4. 10.7 cm flux was 137.2, 137.1, 147.9, 153.9, 155.1, 152.4, and 161, with a mean of 149.2. Estimated planetary A indices were 7, 13, 3, 12, 24, 16, and 14, with a mean of 12.7. Middle latitude A index was 7, 12, 2, 9, 16, 13, and 11, with a mean of 10.
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