Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin ARLP027:
Sunspot activity increased this week, with average daily sunspot numbers going from 49.1 to 62.6. But oddly, average daily solar flux was down slightly from 105.3 to 103.5.
Taking a longer view, solar activity is stronger than it was a year ago, when the average daily sunspot number was 34.7 and average solar flux was 86.9.
Spaceweather.com reported that a Coronal Mass Ejection (CME) missed Earth on July 1, but it pushed dense solar wind plasma toward us, causing a G1-class geomagnetic storm. In the few hours past midnight UTC, planetary K index was 4, then 5. Alaska’s high latitude college A index was 25 on July 2.
Predicted solar flux for the next month is 120 on July 7 – 8, 130 on July 9 – 11, then 120, 125, 110, and 108 on July 12 – 15, then 110, 100, 95 and 98 on July 16 – 19, 95 on July 20 – 21, 98 on July 22 – 23, 100 on July 24 – 25, 102 on July 26, 105 on July 27 – 28, 100 on July 29, 110 on July 30 – 31, 112 on August 1 – 2, 115 on August 3 – 6, 112 on August 7 – 8, 110 on August 9, and 108 on August 10 – 11.
Predicted planetary A index is 14 and 8 on July 7 – 8, 5 on July 9 – 12, 10 on July 13 – 14, then 15, 12, and 10 on July 14 – 17, 8 on July 18 – 21, then 12, 15, 10, and 8 on July 22 – 25, 5 on July 26 – 31, then 8, 25, 12, and 8 on August 1 – 4, and 5 on August 5 – 9.
Sunspot numbers for June 30 through July 6, 2022, were 40, 30, 57, 42, 79, 92, and 98, with a mean of 62.6. The 10.7-centimeter flux was 95.7, 98, 100.2, 102.2, 104.4, 109.4, and 114.6, with a mean of 103.5.
Estimated planetary A indices were 5, 7, 19, 8, 21, 4, and 5, with a mean of 9.8. Middle latitude A index was 5, 8, 17, 11, 18, 4, and 5, with a mean of 9.7.
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.
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