Solar activity bounced back this reporting week, September 8-14, when average daily sunspot numbers jumped from 68 to 92.7, and average solar flux from 125.8 to 141.3.
Fewer CMEs and flares were evident, with average planetary A index declining from 24.6 to 10.7, and middle latitude numbers from 17.4 to 10.6.
New sunspot groups appeared, one on September 8, three on September 10, and one more on September 13. Total sunspot area (in millionths of a solar disc) on September 12-14 rose from 370 to 870 to 1240, the highest value in over a month.
The sunspot number was highest on September 10 at 122.
During this week two years ago, there were no sunspots at all, and average daily solar flux was only 69.7, over 56 points lower than this week, demonstrating the continued progress of Solar Cycle 25.
The latest (Thursday) forecast from space weather folks at Offut AirForce Base shows predicted solar flux peaking at 150 on October 9,but with flux over the next few days following this bulletin less optimistic than the numbers in the bulletin preview in Thursday's ARRL Letter.
Predicted flux values on September 16-17 are 140 and 135, then 125 on September 18-19, 120 on September 20-29, 125 on September 30 through October 6, 130 on October 7-8, then 150, 148, 143 and 140 on October 9-12, then 136, 130, 125 and 120 on October 13-16, 125 on October 17-18, and 120 on October 19-26.
Predicted planetary A index shows moderate levels of geomagnetic activity until October 1-2. The forecast is 15, 18 and 10 on September 16-18, 5 on September 19-23, then 10 on September 24, 14 on September 25-27, 8 on September 28-29, then 22, 50, 30, 20 and 12 on September 30 through October 4, then 15, 12, 10, 8 and 5 on October 5-9, then 10, 8, 5, 15, 20 and 12 on October 10-15, then 5 on October 16-19, then 12 and 10 on October 20-21, and 14 on October 22-24.
The Autumnal Equinox is only a week away!
Nice solar video from last month:
Here is NOAA's latest forecast discussion:
Comments from F.K. Janda, OK1HH:
"Although the Sun was speckled a week ago, all areas were quiet and overall, the Sun's activity was low. After that, activity began to grow rapidly in the northern hemisphere.
"Sunspot group AR3098 grew larger and on September 11, a C6 class flare was registered. The old area AR3088, which was active during the last rotation of the Sun, returned in the southeast solar limb.
"Two solar wind shock waves hit our planet on September 14 at 0630 UTC and 2313 UTC. The second of them significantly expanded the speed of the solar wind, started a disturbance of the Earth's magnetic field and caused very uneven shortwave propagation conditions, especially on routes leading through higher latitudes. Auroral distortion of signals were observed when passing through inhomogeneities in the auroral belt.
"Further similar disturbances can be expected on September 17th, a calm after September 18th and a decrease in solar activity is expected after September 20th."
The following is edited from an email from David Greer, N4KZ in Frankfort, Kentucky:
"With the Sun perking up from its long sleep, one of my favorite bands, 12 meters, is also coming alive. I've worked FT8 DX on 12 meters from time to time for months, but things really came alive for me from 1236-1356 UTC on September 14 when I worked 22 DX stations back-to-back on SSB.
"I called CQ and was answered by a Dutch station and after that, stations just kept calling and calling. I put 22 DX stations in my log. Most were from Europe, but I also worked the Middle East and Northwest Africa, 18 different DX entities all together.
"Some signals were quite strong, mostly because they ran high power with beam antennas but one station was thrilled to make the trip across the pond from Europe because, he said, 'he was running 100 watts to an indoor dipole in his apartment.'
"Some commented it was their first ever 12-meter QSO. I hear that often from stations everywhere. Some say they didn't think anyone ever used 12 meters. Since 2000, I have 12 meter WAS and confirmed 182 DX entities on 12 alone.
"I often call CQ on SSB when the band seems dead, only to have a rare DX station respond, such as VP8LP in the Falkland Islands.
"I was on 12-meter SSB the first night hams in the USA were authorized to use the band in 1985. That night, the band was wild because of a big sporadic-E opening and strong signals were coming from all directions across North America. It was a blast!
"I am fortunate to have a decent station -- 8-element log periodic antenna up 50 feet from a hilltop QTH with a kilowatt amp. But many signals were so strong on September 14 that I am sure others with modest stations could work many DX stations. I had to QRT at 1356 UTC even though others were still calling. I got back on the band later in the day and worked MW0ZZK in Wales. He was 20 over S9.
"Don't forget about 12 meters. When 10 meters is open, 12 is open too. And don't forget about the phone band allocation, which starts at 24.930 MHz in the USA. I've heard some out of band because they didn't know where the band edge was.
"A great propagation tool is the MUF web page operated by KC2G at https://prop.kc2g.com/ . I monitor it constantly. It tells me what bands to check out and where I should aim my antenna. Plus, it has other interesting data in the menu."
Thanks to Dave for mentioning that great web site. I notice it has a section labeled eSSN, which is Effective Sunspot Number, derived from 10.7 cm solar flux. More about eSSN from NorthWest Research Associates, based here in the Seattle area:
Also, I would like to add that often 12 meters is open when 10 meters seems dead.
Here is more crazy solar news:
Here is Newsweek again:
Some solar wind news:
Lucky us! A brand new video, dated today, from Dr. Tamitha Skov, WX6SWW:
Send your tips, reports, observations, questions, and comments to email@example.com.
For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information Service 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 http://arrl.org/w1aw-bulletins-archive-propagation . More good information and tutorials on propagation are at http://k9la.us/ .
Instructions for starting or ending email distribution of ARRL bulletins are at http://arrl.org/bulletins .
Sunspot numbers for September 8 through 14, 2022 were 75, 72, 122, 113, 117, 93, and 57, with a mean of 92.7. 10.7 cm flux was 126.6, 126.2, 135.9, 151.5, 150.4, 154.1, and 144.3, with a mean of 141.3. Estimated planetary A indices were 19, 13, 12, 9, 9, 4, and 9, with a mean of 10.7. Middle latitude A index was 17, 14, 10, 9, 9, 5, and 10, with a mean of 10.6.