ARRL
07/05/2024
Solar activity increased this week, with average daily sunspot numbers rising from 149.6 to 181.6. For some reason, the average daily solar flux decreased from 178 to 175.
Seven new sunspot groups emerged this week, one on June 27, two on June 28, three on June 29, and one more on July 3.
The average daily planetary index rose from 10.3 to 15.6 while the average middle latitude A index rose from 10.1 to 11.6.
On Friday, June 28, a CME caused a severe G4 class geomagnetic storm. Middle latitude A index was 32 and planetary A index was 59, much higher than Alaska's college A index (36).
Predicted solar flux is 175, 172 and 168 on July 5 to 7, 160 on July 8 and 9, 155 on July 10 and 11, 170 on July 12 and 13, 180 on July 14, 175 on July 15 to 17, 180 on July 18 to 21, 185 on July 22, 180 on July 23 to 29, 175 on July 30, 170 on July 31 through August 9 and 180 on August 10.
Predicted planetary A index is 8, 5, 5, 12, and 10 on July 5 to 9, 5 on July 10 to 13, then 10, 10, and 8 on July 14 to 16, 5 on July 17 to 19, then 10 and 8 on July 20 and 21, and 5 on July 22 through August 9, and 10 on August 10 and 11.
"Geomagnetic activity forecast for July 5 to 11, 2024
Quiet: July 5 to 7, 9 and 10
Unsettled: July 7 and 8, 11
Active: possible July 8, 11
Minor storm: 0
Major storm: 0
Severe storm: 0
"Next week, we expect at most quiet to unsettled conditions. More unsettled conditions with possible isolated active events are possible about July 7 and 8, and also at the end of the current forecast period, about Thursday, July 11." Tomas Bayer RWC Prague Institute of Geophysics of the ASCR Department of Geomagnetism Budkov Observatory
2023 NOAA updates:
w.weather.gov/news/102523-solar-cycle-25-update
Latest from Tamitha Skov, KX6SWW:
Blackout: https://bit.ly/45R9PqD
Send your tips, reports, observations, questions and comments to k7ra@... . When reporting observations, don't forget to tell us which mode you were operating.
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service web page at, http://arrl.org/propagation-of-rf-signals .
For an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .
An archive of past propagation bulletins is at
More good information and tutorials on propagation are at
http://k9la.us/
Also, check this: https://bit.ly/3Rc8Njt
Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .
Sunspot numbers for June 27 through July 3 2024 were 146, 162, 205, 192, 192, 192, and 182, with a mean of 181.6. 10.7 cm flux was 182.5, 180.7, 186.4, 173.8, 170.6, 163.8, and 167.4, with a mean of 175. Estimated planetary A indices were 9, 59, 14, 11, 6, 5, and 5, with a mean of 15.6. Middle latitude A index was 11, 32, 11, 10, 5, 6, and 6, with a mean of 11.6.
