Average daily sunspot numbers declined, but the average daily solar flux increased. Sunspot averages were 181.9 last week and 130.6 this week. The average daily solar flux increased from 179.4 to 190.5.
Two new sunspot groups emerged on July 14, as well as three more on July 17, and another two on July 19.
The average daily planetary and middle latitude A indices were both 12.9 this week, rising from 8.6 and 8.1.
Predicted solar flux is 188 on July 20 – 23; 186, 184, 186, and 160 on July 24 – 27; 165 on July 28 – 29; 170 on July 30 – 31; 165 on August 1 – 4; 170, 175, 175, and 170 on August 5 – 8; 165 on August 9 – 11; 170 on August 12; 175 on August 13 – 14, and 170 on August 15 – 19.
The predicted planetary A index is 28, 20, and 12 on July 20 – 22; 5 on July 23 through August 2; 10 and 8 on August 3 – 4; 5 on August 5 – 14, then 12, 8, and 8 on August 15 – 17.
CNN presented a smart piece on the sunspot cycle peaking sooner than expected:
Cosmos published an article about a double-peaked solar flare:
Sunspot numbers for July 13 – 19, 2023, were 146, 141, 96, 99, 149, 142, and 141, with a mean of 130.6. The 10.7-centimeter flux was 202.9, 180.6, 178.5, 184.3, 180, 218.5, and 188.9, with a mean of 190.5. Estimated planetary A indices were 7, 20, 8, 10, 24, 16, and 5, with a mean of 12.9. Middle latitude A index was 9, 17, 9, 13, 19, 16, and 7, with a mean of 12.9.
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.
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