ZCZC AP29QST de W1AW Propagation Forecast Bulletin 29 ARLP029From Tad Cook, K7RASeattle, WA July 21, 2023To all radio amateurs
SB PROP ARL ARLP029ARLP029 Propagation de K7RA
Average daily sunspot numbers declined, but average daily solar fluxincreased. Sunspot averages were 181.9 last week, and 130.6 thisweek. Average daily solar flux increased from 179.4 to 190.5.
Two new sunspot groups emerged on July 14, three more on July 17 andanother two on July 19.
Average daily planetary and middle latitude A index were both 12.9this week, rising from 8.6 and 8.1.
Predicted solar flux is 185 on July 21-23, then 180, 178, 175 and170 on July 24-27, 165 on July 28-29, 170 on July 30-31, 165 onAugust 1-4, then 170, 175, 175 and 170 on August 5-8, 165 on August9-11, 170 on August 12, 175 on August 13-14, and 170 on August15-19, 160 on August 20-23, 165 on August 24-25, then 170 on August26-27 and 165 on August 28-31.
Predicted planetary A index is 20, 12, 8, 12 and 10 on July 21-25, 5on July 26 through August 2, then 10 and 8 on August 3-4, 5 onAugust 5-14, then 12, 8 and 8 on August 15-17, and 5 on August18-29.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth'sIonosphere for July 20, 2023 from OK1HH.
"We've seen another seven days of mostly moderate solar activity,with almost daily eruptions of moderate magnitude on the Sun. Someof these have been the source of CMEs. If the Earth has beenaffected by them, a geomagnetic disturbance followed, with a drop inMUF and a worsening of HF propagation in the process.
As predicted, the expected CME hit the Earth's magnetic field on theafternoon of 14 July (as part of the Bastille Day celebrations, butnot nearly as strongly as in 2000).
Another CME left the Sun on 14 July, and yet another on July 15.Because the cloud of later ejected solar plasma was faster, itcannibalized the previous CME. Together, they hit the Earth on July18.
But by then AR3363 had already produced a significant long-lastingM6-class solar flare, and energetic protons accelerated by thisflare reached the Earth and caused a radiation storm. Although MUFswere quite high, HF conditions were adversely affected by frequentoccurrences of attenuation.
Another CME hit the Earth on 20 July, registered by the Earth'smagnetic field at 1708 UTC.
Further developments were predicted up to G1 to G2 class geomagneticstorms, with a small probability also of G3, but by then this reportwill have been completed and sent out.
Finally, just a little note on the consequences of global change: ithas been manifested in the last eleven-year cycles, in the Earth'stroposphere it is the result of warming, but in the ionosphere it israther the opposite. It has been the subject of a number ofscientific papers in recent years.
It is crucial for us, for amateur radio practice, that the currentMUFs are lower than those calculated from sunspot counts for most ofthe twentieth century. Therefore, we should input Ri (or solar fluxSFU) into forecast programs lower than what is currently measuredand published.
F.K. Janda, A.R.S. OK1HH http://ok1hh.nagano.cz/ "
News from N8II in West Virginia.
"The bands are in much better shape than most hams realize; activitylevels are normally quite low this summer. In the IARU contest Iobserved 15M open to Europe through 0300 UTC and I had QSOs withIndonesia, China, Nepal, Japan, Central/Western Siberia, Kazakhstan,and the Philippines in the 2300-0300 UTC period.
I copied GR2HQ (Great Britain HQ station) on 10M CW at 0140 UTC. At1100 UTC on 15M EU and Central/West Asia were very loud and Istarted running a pile up on CW.
The Far East was also in on 15M around 1400 UTC Saturday when Iworked a loud Japanese station.
During the evening/night EU signals were extremely loud on 20M. Ialso worked a few EU on 10M 1300-1400 UTC Saturday thanks toSporadic E and also caught Z30HQ (Macedonia HQ) on 10M CW Sundayabout 1130 UTC. I worked 697 QSOs concentrating on DX on the highbands in less than 12 hours with 100 W.
Africa is workable on 10-15M well into our evening as are SouthPacific stations.
Sporadic E this year seems somewhat attenuated, but Es was good fromhere and great from the Central/Western USA during the June VHFcontest. I made about 170 CW/SSB QSOs."
CNN presented a smart piece on the sunspot cycle peaking sooner thanexpected. https://bit.ly/3rzNJJ6
Double peaked flare. https://bit.ly/46ZoznE
Astronomy club observes sunspots. https://bit.ly/46SaacR
Aurora. https://bit.ly/44FxM2U
Scientific American. https://bit.ly/3rHzGkB
Early peak. https://bit.ly/44Aa7AF https://bit.ly/3rEa0Wj
Cannibal eruption. https://bit.ly/3Q5dv1W
Great video of eruption. https://youtu.be/YOzHHM4B4gA
The latest from Space Weather Woman Dr. Tamitha Skov, WX6SWW.
https://youtu.be/KsKDVOuboyw
Send your tips, reports, observations, questions and comments to
[email protected]. When reporting observations, don't forget to tellus which mode you were operating.
For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation and the ARRL Technical InformationService at http://arrl.org/propagation-of-rf-signals . For anexplanation of numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere .
Also, check this article from September, 2002 QST:
https://www.arrl.org/files/file/Technology/tis/info/pdf/0209038.pdf
An archive of past propagation bulletins is at
http://arrl.org/w1aw-bulletins-archive-propagation . More goodinformation and tutorials on propagation are at http://k9la.us/
Instructions for starting or ending email distribution of ARRLbulletins are at http://arrl.org/bulletins
Sunspot numbers for July 13 through 19, 2023 were 146, 141, 96, 99,149, 142, and 141, with a mean of 130.6. 10.7 cm 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, witha mean of 12.9. Middle latitude A index was 9, 17, 9, 13, 19, 16,and 7, with a mean of 12.9.NNNN/EX