Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin:

A new sunspot group emerged on August 18 and August 21, and two more emerged on August 23. Overall, solar activity was down slightly, with the average daily sunspot number declining from 60.8 to 58.7, and average solar flux from 123.7 to 104.5.

Planetary A index changed from an average of 11.7 to 12.6, and middle latitude A index, measured at a single magnetometer in Virginia, was 11, after an average of 10 last week.

The Wednesday night forecast from the 557^th Weather Wing at Offutt Air Force Base showed a probable solar flux peak at 130 on September 11 for the near term.

Predicted solar flux is 105 on August 25 – 26; 108 on August 27 – 28; 110 on August 29 through September 1; 114 on September 2; 116 on September 3 – 4; 112 on September 5; 108 on September 6 – 7; 115, 120, 124, and 130 on September 8 – 11; 128, 120, 118, 105, and 102 on September 12 – 16; 98 on September 17 – 18; 96 on September 19 – 21; 94 on September 22 – 24, and 92, 98, and 100 on September 25 – 27.

Predicted planetary A index has some surprises in store: 5 on August 25 – 26; 8 on August 27 – 28; 5 on August 29 through September 2; then jumping way up to 30, 38, and 20 on September 3 – 5; 15, 18, 10, 12, and 8 on September 6 – 10; 5 on September 11 – 12; 12, 15, and 10 on September 13 – 15; 8 on September 16 – 17; 25, 15, and 8 on September 18 – 20; 5 on September 21 – 22; 12 on September 23, and 8 on September 24 – 26.

My main power supply failed on August 21, so for a week or two I will be unable to make on-the-air observations as I await factory repair.

News about a large sunspot can be found at https://inshorts.com/en/news/huge-sunspot-on-suns-surface-grows-10-times-in-size-in-48-hours-pic-surfaces-1661347322422.

Sunspot numbers for August 18 through 24 were 83, 74, 56, 56, 44, 52, and 46, with a mean of 58.7. The 10.7-centimeter flux was 116.5, 105.4, 101.5, 97, 102.6, 100.9, and 107.8, with a mean of 104.5. Estimated planetary A indices were 26, 20, 14, 14, 7, 4, and 3, with a mean of 12.6. Middle latitude A index was 19, 15, 16, 13, 7, 3, and 4, with a mean of 11.

Send your tips, questions, or comments to k7ra@arrl.net.

A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…” and check out the Propagation Page of Carl Luetzelschwab, K9LA.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Share your reports and observations.

Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin:

At 2334 UTC on August 17, the Australian Space Forecast Centre issued a geomagnetic disturbance warning.

“Periods of G1 conditions expected during August 19 – 20 due to the combination of coronal hole high — speed wind stream and several coronal mass ejections observed in the last few days. There is a chance of isolated periods of G2 over August 19 – 20.”

Local TV newscasts in Seattle noted the possibility of an aurora on Thursday night, although observers would need to travel to dark areas away from the city for any chance of successful viewing. In fact, they recommended using a camera pointed north using a long exposure time.

Last week, we noted increasing solar activity, and it continued. Average daily sunspot numbers increased from 65.4 to 95.6, and average daily solar flux increased from 111.9 to 123.7.

Predicted solar flux is 125 on August 18 – 19; 120 on August 20; 115 on August 21 – 23; 110 and 95 on August 24 – 25; 94 on August 26 – 27; 96, 98, 100, 108, and 114 on August 28 – September 1; 116 on September 2 – 3; 112 on September 4; 108 on September 5 – 6; 115, 120, 124, and 126 on September 7 – 10; 124 on September 11 – 12; 122, 118, 112, 108, and 102 on September 13 – 17, and 100 on September 18 – 19.

Predicted planetary A index is 56 (!), 30, 18, and 8 on August 18 – 21; 5 on August 22 – 26; 12 on August 27; 8 on August 28 – 30; 5 on August 31 – September 2; 24, 28, 18, and 10 on September 3 – 6; 14, 8, 10, and 8 on September 7 – 10; 5, 5, 20, and 15 on September 11 – 14; 12, 12, and 8 on September 15 – 17, and 5 on September 18 – 20.

Tamitha Skov says, “Don’t worry, this is not a Carrington Event,” in an 84-minute video titled, “Incoming Solar Storm Crush.”

Even Newsweek is reporting it.

And of course, British Tabloids

and NOAA.

Sunspot numbers for August 11 – 17, 2022, were 58, 97, 116, 104, 92, 119, and 83, with a mean of 95.6. The 10.7-centimeter flux was 114.8, 119.5, 124.2, 125.5, 130.6, 128.5, and 122.7, with a mean of 123.7. Estimated planetary A indices were 16, 7, 10, 7, 6, 5, and 31, with a mean of 11.7. Middle latitude A index was 12, 6, 10, 9, 6, 5, and 22, with a mean of 10.

Send your tips, questions, or comments to k7ra@arrl.net.

A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…” and check out the Propagation Page of Carl Luetzelschwab, K9LA.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Share your reports and observations.

Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin:

Solar activity continued to decline this week, with the average daily sunspot number dropping from 91.1 to 36.6, and average solar flux at 95.7, down from 107.6 the week prior.

We have not seen lower values since mid-April in bulletin ARLP015

with average sunspot number at 34.4, and the end of February in ARLP008 with the average solar flux at 95.4.

This was noticeable over the past week on 10 and 12 meters, but there must still be some daily sporadic E, from what I have seen on an email list devoted to 10-meter propagation beacons. I have one myself — K7RA/B transmitting CW from CN87uq on 28.2833 MHz.

The outlook from the United States Air Force space weather group shows a meager forecast for solar flux, according to forecasters Sadovsky and Ciopastu on Wednesday.

Predicted solar flux over the next month never rises above 100, having values of 100 for August 4 – 7; 98 and 96 on August 8 – 9; 98 on August 10 – 14; 100 on August 15 – 16; 98 on August 17 – 18; 96, 96, and 98 on August 19 – 21; 96 again on August 22 – 23; 92 on August 24 – 28; 90 and 92 on August 29 – 30; 94 on August 31 – September 1; 96 on September 2 – 3, and 98 on September 4 – 10.

Predicted planetary A index is 8 on August 4; 5 on August 5 – 7; 8, 14, and 12 on August 8 – 10; 8 on August 11 – 12; 5 on August 13 – 16; 22 on August 17; 15 on August 18 – 19; 8 on August 20 – 21; 5 on August 22 – 25; 10 and 12 on August 26 – 27; 5 on August 28 – 29; 12 and 10 on August 30 – 31, and 5 on September 1 – 6.

Sunspot numbers for July 28 – August 3 were 50, 40, 27, 39, 32, 31, and 37, with a mean of 36.6. The 10.7-centimeter flux was 93, 90.8, 94.3, 95.4, 97.8, 98.8, and 99.9, with a mean of 95.7. Estimated planetary A indices were 7, 4, 7, 11, 8, 9, and 8, with a mean of 7.7. Middle latitude A index was 9, 6, 8, 12, 8, 10, and 7, with a mean of 8.6.

Send your tips, questions, or comments to k7ra@arrl.net.

A comprehensive K7RA Solar Update is posted Fridays on the ARRL website. For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…” and check out the Propagation Page of Carl Luetzelschwab, K9LA. A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website