Both the average daily sunspot numbers and solar flux increased this week. Average daily sunspot numbers rose from 118.6 to 133.4, while average solar flux went from 143.2 to 161.2.

Geomagnetic indicators were more active. Average daily planetary A index went from 9.6 to 17.1, while average middle latitude A index rose from 9.6 to 14.4.

Predicted solar flux is 160 on May 25 – 26; 165 on May 27; 160 on May 28; 155 on May 29 – 30; 160 and 150 on May 31 and June 1; 155 on June 2 – 4; 160, 165, 160, 155, and 150 on June 5 – 9; 145 on June 10 – 11; 150 on June 12; 155 on June 13 – 14; 160 on June 15; 165 on June 16 – 17; 160, 155, and 150 on June 18 – 20; 155 on June 21 – 22, then 160, 165, and 160 on June 23 – 25.

Predicted planetary A index is 12, 15, 8, 5, and 8 on May 25 – 29; 5 on May 30 through June 1; 16, 8, 10, and 8 on June 2 – 5; 5 on June 6 – 15, then 12, 10, 5, 18, 22, 15, and 10 on June 16 – 22.

Check out a video of the beautiful auroras explained here:

https://tinyurl.com/2zxdmpu6

Check out sunspot images at these links:

https://tinyurl.com/muaakxn9

https://www.popsci.com/science/sun-images-powerful-solar-telescope/ Sunspot numbers for May 18 through 24, 2023, were 121, 155, 138, 140, 97, 130, and 153, with a mean of 133.4. 10.7-centimeter flux was 150.6, 164.6, 169.6, 163.4, 161.5, 154.9, and 164.1, with a mean of 161.2. Estimated planetary A indices were 3, 9, 35, 28, 21, 12, and 12, with a mean of 17.1. Middle latitude A index was 8, 10, 26, 19, 17, 11, and 10, with a mean of 14.4.

Many thanks to all that have checked into the Sunday night nets over this past season. The net will be on vacation until October 1, 2023. Meanwhile keep checking the web page for any updates to the repeater and enjoy your summer and early fall. See you all next October!

This reporting week, May 11 – 17, the average daily sunspot number was marginally lower at 118.6 compared to 119.3 last week.

The average daily solar flux dropped from 167.8 to 143.2.

Geomagnetic indicators were quieter, with both planetary and middle latitude A index at 9.6. Last week the two numbers were 15.1 and 11.9.

10.7-centimeter solar flux is forecast to peak at 165 on June 8.

The predicted solar flux numbers are 140 and 138 on May 18 – 19; 135 on May 20 – 21; 130 on May 22 – 24, then 154, 140, and 145 on May 25 – 27; 155 on May 28 – 30; 160 on May 31 and June 1; 155 on June 2 – 3; 160 on June 4 – 7, then 165, 160, 150, 145, and 150 on June 8 – 12, then 155 on June 13 – 17.

Predicted planetary A index is 5 on May 18 – 19; 8 on May 20 – 21; 5 on May 22 – 23, then 12, 15, and 15 on May 24 – 26; 10, 10, and 8 on May 27 – 29; 5 on May 30 through June 1, then 16, 12, 16, and 12 on June 2 – 5; 8 on June 6 – 8, and 5 on June 9 – 18.

Check out NASA’s sunspot picture from May 17 at https://bit.ly/458DrPw.

Check out a video of the recent solar eruption at https://www.youtube.com/watch?v=Rm7M5pqjCgY.

Read about how the solar flare caused a radio blackout at https://bit.ly/434c5bw.

Read about a solar storm threat at https://bit.ly/3pSK4p2.

Sunspot numbers for May 11 through 17, 2023, were 152, 134, 120, 109, 103, 106, and 106, with a mean of 118.6. 10.7-centimeter flux was 163.4, 149.1, 143.8, 139.7, 134.5, 134.3, and 137.9, with a mean of 143.2. Estimated planetary A indices were 9, 19, 13, 8, 6, 8, and 4, with a mean of 9.6. Middle latitude A index was 10, 15, 12, 9, 6, 10, and 5, with a mean of 9.6.

There was a modest increase in solar activity this reporting week, May 4 – 10.

Average daily sunspot numbers nudged up from 114 to 119.3, and average daily solar flux went up from 151.5 to 167.1.

Average daily planetary A index changed from 13.6 to 15.1, and average middle latitude A index remained the same at 11.9.

Predicted solar flux is 170, 168, 166, 162, and 160 on May 11 – 15; 162 on May 16 – 17; 155 on May 18 – 21; 150 on May 22; 145 on May 23 – 25, then 140 and 145 on May 26 – 27; 155 on May 29 – 30; 160 on May 31 through June 1; 155 on June 2 – 3; 160 on June 4 – 7, then 165, 160, and 150 on June 8 – 10.

Predicted planetary A index is 46, 30, 12, and 8 on May 11 – 14; 5 on May 15 – 22, then 12 and 20 on May 23 – 24; 15 on May 25 – 26; 10 on May 27 – 28; 8 on May 29; 5 on May 30 through June 1, then 16, 12, 16, and 12 on June 2 – 5; 8 on June 6 – 8, and 5 on June 9 – 13.

Read about possible geomagnetic stormy space weather at:

https://www.space.com/sun-reverse-sunspot-auroras-supercharge.

Sunspot numbers for May 4 through 10, 2023, were 139, 90, 99, 99, 103, 151, and 154, with a mean of 119.3. 10.7-centimeter flux was 162, 161.9, 151.8, 157.2, 171.9, 194.7, and 170.1, with a mean of 167.1. Estimated planetary A indices were 6, 5, 30, 9, 16, 14, and 26, with a mean of 15.1. Middle latitude A index was 7, 4, 21, 8, 13, 11, and 19, with a mean of 11.9

At 0134 UTC on April 27, The Australian Space Weather Forecasting Centre of the Australian Bureau of Meteorology issued a geomagnetic disturbance warning, stating, “An equatorial coronal hole is currently elevating solar wind speeds. Combined with the anticipated impact from a recent CME on April 27, geomagnetic activity is expected to be at G0-G1 levels over April 27 – 28, with a slight chance of an isolated period of G2.”

Solar and geomagnetic indicators moved in opposite directions this week. Average daily sunspot numbers over April 20 – 26 made a dramatic drop from 146.9 to 91.4, and average daily solar flux dropped from 164.5 to 139.4.

Average daily planetary A index more than tripled from 8.1 to 26.9, while average middle latitude A index more than doubled from 7.3 to 15.6.

Solar wind and explosions caused all of this grief.

Spaceweather.com reported that on April 21, a large magnetic filament on the sun exploded and hurled debris toward Earth.

Later, they reported that on April 23, at 1737 UTC a CME hit Earth, which sparked a severe G4-class geomagnetic storm. Aurora was visible as far south as southern New Mexico and Texas.

The planetary K index went as high as 8 over April 23 – 24.

Predicted solar flux over the next month is 135 on April 27 – 30; 140 on May 1 – 6, then 145, 150, 155, 160, and 165 on May 7 – 11; 170 on May 12 – 13, then 165, 160, 155, 150, 145, and 140 on May 14 – 19; 135 on May 20 – 21; 130 and 125 on May 22 – 23; 120 on May 24 – 25, and 125, 130, and 135 on May 26 – 28.

Predicted planetary A index is 18, 25, and 12 on April 27 – 29; 8 on April 30 through May 3, then 10, 8, 12, and 10 on May 4 – 7; 8 on May 8 – 9, then 5, 5, and 12 on May 10 – 12; 5 on May 13 – 15; 8 on May 16 – 17; 5 on May 18 – 22, then 15 and 18 on May 23 – 34, and 15 on May 25 – 27.

Here is a link to the aurora as observed in China:

https://bit.ly/41KyY3w

Here is a link to explaining the aurora:

https://bit.ly/3n7ROm2

Sunspot numbers for April 20 through 26, 2023, were 97, 114, 87, 86, 88, 87, and 81, with a mean of 91.4. 10.7-centimeter flux was 147, 151.2, 141.2, 135.2, 133.9, 130.7, and 136.5, with a mean of 139.4. Estimated planetary A indices were 5, 9, 7, 66, 76, 10, and 15, with a mean of 26.9. Middle latitude A index was 5, 8, 6, 32, 39, 7, and 12, with a mean of 15.6.

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.

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