Eleven new sunspot groups emerged over the past week, August 10 – 16, 2023, but average solar indicators declined.
There were two new sunspot groups on August 11, three more on
August 13, another on August 14, two more on August 15, and three more on August 16.
The average daily sunspot numbers declined from 108.9 to 95.7, while the average daily solar flux dropped from 166.4 to 154.2.
Predicted solar flux is 160 on August 17 – 24; 162, 160, and 164 on August 25 – 27; 168 on August 28 – 31; 165, 163, and 160 on September 1 – 3; 158, 155, 152, and 150 on September 4 – 7; 148, 142, 140, and 130 on September 8 – 11; 135 on September 12 – 14, and 145, 150, and 155 on September 15 – 17.
Predicted planetary A index is 15, 12, and 8 on August 17 – 19; 5 on August 20 – 25; 12 on August 26; 5 on August 27 through September 5; 10, 8, and 8 on September 6 – 8; 5 on September 9 – 11, and 12, 15, 12, and 8 on September 12 – 15.
Look for comments from readers concerning the transition from summer to fall conditions in Friday’s bulletin.
Sunspot numbers for August 10 through 16, 2023, were 83, 105, 61, 89, 85, 107, and 140, with a mean of 95.7. The 10.7-centimeter flux was 155.7, 152.8, 148.3, 150.4, 154, 158.1, and 160.1, with a mean of 154.2. Estimated planetary A indices were 7, 5, 8, 5, 5, 5, 5, 5, 5, 4, and 8, with a mean of 6. The middle latitude A index was 8, 6, 10, 7, 6, 7, and 10, with a mean of 7.7.
A comprehensive 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.
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