10/26/23 Solar report

The recent decline in solar activity continues. The weekly average daily sunspot numbers, starting with ARLP039 on September 21, were 170.6, 128.6, 144.1, and 89.4. This week’s average daily sunspot number was 41.9. The weekly average daily solar flux for the same period was 168.8, 155.6, 159.1, 145.1, and 123.5.

On October 25, Spaceweather.com noted, “Solar Cycle 25 roared to life in 2021 – [2023], dashing predictions of a weak solar cycle. Forecasters have since been expecting a robust Solar Max in 2024 or 2025. Suddenly, however, sunspot counts are dropping.” They also noted that temporary lulls are common in strong sunspot cycles, and strong activity should resume soon, with a cycle peak occurring within the next 2 years. They provided a recent link to the NOAA Space Weather Scale at https://bit.ly/3FyVWko.

Three new sunspot groups appeared this week on October 20 – 22.

Predicted solar flux is 125 on October 26 – 28; 120 on October 29 through November 1; 150 on November 2 – 5; 140 on November 6 – 9; 135 on November 10 – 11; 145, 140, 135, and 135 on November 12 – 15; 140 on November 16 – 18; 135 and 140 on November 19 – 20, and 145 on November 21 – 24.

Predicted planetary A index is 5, 8, 5, 5, 18, and 10 on October 26 – 31; 5 on November 1 – 8; 12 and 8 on November 9 – 10; 5 on November 11 – 12; 12 on November 13 – 14; 10 and 8 on November 15 – 16; 5 on November 17 – 22, and 8 on November 23 – 26.

Jon Jones, N0JK, QST columnist for “The World Above 50 MHz QST” wrote:

“The weekend of October 20 – 22 had some outstanding propagation on 6 meters.

On the afternoon of Saturday, October 21, there was E-layer or sporadic-E propagation linking to trans-equatorial paths to the [South] Pacific from the Midwest. N0LL copied FK8CP and ZL1RS on just a ham stick vertical antenna while driving from Salina to his home in Smith Center, KS. He later worked E51WL from his home around 2130Z.

I was staying at the La Quinta Inn in Scottsdale for the weekend [and] had my MFJ-9406 [with me]. Using a dipole antenna in the hotel room, I copied N0LL EM09, N0KQY DM998, and N0OT DM88 on 6-meter Es, calling DX stations around 1945Z. Es in October are rare, and Es links rarer still.

[On October 22], I managed to work W5JAY EM26 on [6-meter] FT8 via Es at 0136 [UTC.] Power was 7 watts to the indoor dipole. East coast stations were working the South Pacific on Es links to TEP.

That next afternoon, Arizona had Es link[s] to TEP to South America. I copied XE1H DL80 at the first Es hop. 231022_233300 50.313 Rx FT8 -8 0.2 1612 CQ XE1H DL80.

October 24 at 2335 UTC copied PY5CC GG54 via Es link to TEP.

Spaceweather.com noted a coronal mass ejection (CME) impact [on] October 20. The active geomagnetic field boosted the TEP MUF and may have sparked some of the sporadic -E as well.

Note that this weekend is the SSB portion of the CQ World Wide DX Contest.

See https://www.cqww.com/ for more information.

Sunspot numbers for October 19 – 25, 2023, were 39, 56, 65, 48, 25, 34, and 26, with a mean of 41.9. The 10.7-centimeter flux was 128.7, 125.7, 122.6, 118.8, 122.1, 121.1, and 125.8, with a mean of 123.5. Estimated planetary A indices were 10, 8, 22, 8, 3, 4, and 4, with a mean of 8.4. The middle latitude A index was 8, 8, 13, 7, 2, 2, and 3, with a mean of 6.1.

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.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website.

Share your reports and observations.

A weekly, full report is posted on ARRL News.

Solar Report 10/19/23

Sunspot activity dropped dramatically this week, with only two new sunspot groups emerging on October 14 and 16.

Compared to last week, the average daily sunspot number slipped from 144.1 to 89.4, and the average daily solar flux dropped from 159.1 to 145.1.

Average daily planetary A index changed from 7.6 to 6.4, and the average daily middle latitude A index went from 8.3 to 5.

Predicted solar flux is 135 on October 19 – 20; 140 on October 21 – 26; 145 on October 27 – 28; 150 on October 29 – November 5; 140 on November 6 – 9; 135 on November 10 – 11; 145 and 140 on November 12 – 13; 135 on November 14 – 15, and 140 on November 16 – 18.

Predicted planetary A index is 18, 22, 24, 8, 10, and 8 on October 19 – 24; 5 on October 25 – 26; 8 on October 27 – 30; 10 and 12 on October 31 – November 1; 5 on November 2 – 8; 12 on November 9 – 10; 5 on November 11 – 12; 12 on November 13 – 14, and 10 and 8 on November 15 – 16.

See a report about a possible October 19 geomagnetic storm at https://bit.ly/3rQaZDk. Sunspot numbers for October 12 – 18, 2023, were 126, 91, 100, 92, 106, 57, and 54, with a mean of 89.4. The 10.7-centimeter flux was 157.1, 149, 148.2, 144.6, 144, 137.3, and 135.3, with a mean of 145.1. Estimated planetary A indices were 4, 13, 8, 4, 4, 3, and 9, with a mean of 6.4. Middle latitude A index was 3, 11, 6, 2, 3, 2, and 8, with a mean of 5.

Solar Report 10/13/23

The numbers looked better during this reporting week, October 5 – 11, 2023.

The average daily sunspot numbers rose from 128.6 to 144.1, and the average solar flux rose from 155.6 to 159.1.

The average daily planetary A index decreased from 9.1 to 7.6, as did the average middle latitude A index from 8.9 to 8.3.

For some reason, the middle latitude numbers were not available from Fredericksburg, Virginia, so we used the data from Boulder, Colorado.

Nine new sunspot groups emerged this week, with two on October 5, one on October 7, two on October 8, one on October 9, one on October 10, and two on October 11.

HF conditions have been excellent, as the season turns deeper into fall in the Northern Hemisphere. I really noticed a difference on 10, 12, and 15 meters.

The predicted solar flux is 158 and 156 on October 12 – 13; 155 on October 14 – 16; 152 on October 17 – 18; 148 on October 19 – 20; 150, 152, 154, 154, and 158 on October 21 – 25; 160 on October 26 – 28; 158 on October 29 – 30; 156 on October 31 through November 1; 155, 156, 156, 158, and 160 on November 2 – 6; 158 on November 7 – 8, and 156 on November 9 – 10.

The predicted planetary A index is 12 on October 12 – 13; 10, 8, 5, 12, and 10 on October 14 – 18; 5 on October 19 – 30; 15 and 12 on October 31 through November 1; 5 on November 2 – 5; 10, 8, and 10 on November 6 – 8; 15 on November 9 – 10, and 8 on November 11.

Check out these links:

The 15,000-year history of extreme solar events:

https://bit.ly/3FctowT

Commercial space companies approach their first solar maximum:

https://bit.ly/46Cx6Ma

Korean records from the 14th to 19th century reveal sunspot cycle history:

https://bit.ly/3ZUo2Af

Safely watch the eclipse with a disco ball (I don’t actually know if this is safe):

https://bit.ly/3tBhgmz

Ring of fire solar eclipse:

https://wapo.st/3rNEHIY

https://bit.ly/3FeOQSc

Solar polarity flip:

https://bit.ly/3LWZ7WF Sunspot numbers for October 5 – 11, 2023, were 179, 138, 145, 149, 129, 120, and 149, with a mean of 144.1. The 10.7-centimeter flux was 156.1, 155.3, 157.2, 157.1, 165.5, 164.4, and 158, with a mean of 159.1. Estimated planetary A indices were 16, 9, 5, 7, 8, 4, and 4, with a mean of 7.6. The middle latitude A index was 17, 8, 4, 10, 9, 6, and 4, with a mean of 8.3.


Week of Oct. 5 Solar Report

Seven new sunspot groups emerged this past week, but overall solar activity has declined.

It’s great to see the sun covered in sunspots; see Spaceweather.com’s recent image of the sun at https://www.spaceweather.com/images2023/04oct23/hmi1898.gif.

You can change the /04oct23/ field in the above URL to view a solar image of any date. By loading images of consecutive dates, you can initiate an animation using the back and forward buttons on your browser.

We are currently enjoying improved HF propagation with the change of seasons after the autumnal equinox. This is particularly noticeable on 12 and 10 meters.

Read an optimistic news story about the current solar cycle at https://cdapress.com/news/2023/oct/02/were-strong-solar-cycle/, and another report at https://bit.ly/3RMPjT1.

One new sunspot group appeared on September 30, followed by three

Solar disk image taken October 5, 2023. [Photo courtesy of NASA SDO/HMI]

more on October 1, and then one each on October 2, 3, and 4.

The average daily sunspot number declined from 170.6 to 128.6, while the average daily solar flux went from 168.8 to 155.6.

Geomagnetic indicators were quieter. The average daily planetary A index went from 17 to 9.1, and the average daily middle latitude A index declined from 13.7 to 8.9.

The outlook for next month has the solar flux at 160 on October 5; 162 on October 6 – 8; 155 on October 9 – 10; 150 and 160 on October 11 – 12; 158 on October 13 – 14; 156 on October 15 – 17; 154 on October 18 – 20; 152 on October 21; 154 on October 22 – 23; 156 and 158 on October 24 – 25; 160 on October 26 – 28; 162 on October 29 – 31, and 164 on November 1 – 3.

If we use this forecast as a guide, we can predict the solar flux average for the next reporting week, October 5 – 11, to be 2.4 points higher than that of this week.

Predicted planetary A index is 12 on October 5 – 6; 15, 8, and 5 on October 7 – 9; 8 on October 10 – 11; 5 on October 12 – 21; 10 and 8 on October 22 – 23; 5 on October 24 – 28, and then 15, 12, 8, 15, and 8 on October 29 – November 2. Sunspot numbers for September 28 – October 4, 2023, were 109, 102, 106, 136, 146, 150, and 151, with a mean of 128.6. The 10.7-centimeter flux was 147.8, 155, 159.1, 161.1, 157.4, 153.7, and 155, with a mean of 155.6. Estimated planetary A indices were 6, 12, 10, 9, 9, 8, and 10, with a mean of 9.1. Middle latitude A index was 5, 13, 11, 9, 10, 6, and 8, with a mean of 8.9.

A propagation bulletin archive is available. For customizable propagation charts, visit the VOACAP Online for Ham Radio website. Share your reports and observations.



Solar Report 9-21-23

Nine new sunspot groups appeared this week, but the average daily sunspot numbers were lower.

A new sunspot group appeared every day on September 15 – 17; four more appeared on September 18, and one appeared each day on September 19 – 20, 2023.

The average daily sunspot numbers declined from 138.1 to 118.4, while the average daily solar flux declined from 159.9 to 149.3.

The autumnal equinox in the Northern Hemisphere is Friday, September 22, 2023. The change in seasons has been evident with improving conditions on 10 and 12 meters.

A fast-moving coronal mass ejection (CME) hit Earth on September 18, sparking dramatic displays of aurora across the northern tier of North America, and in Europe as far south as France.

Alaska’s college A index was 49 and 61 on September 18 – 19, while the planetary A index was 30 and 49.

Predicted solar flux is 155, 152, 153, and 155 on September 21 – 24; 160 on September 25 – 27; 135 on September 28 – 30;130, 135, 130, and 135 on October 1 – 4; 140 on October 5 – 6; 135 on October 7 – 8; 140, 145, and 145 on October 9 – 11, 150, 150, 155, and 150 on October 12 – 15, and 155, 150, 145, and 145 on October 16 – 19.

Predicted planetary A index is 8 and 15 on September 21 – 22; 12 on September 23 – 26; 5, 8, 12, and 8 on September 27 – 30; 5 on October 1 – 11; 8 on October 12, and 5 on October 13 – 19. Sunspot numbers for September 14 – 20, 2023, were 110, 96, 88, 94, 139, 143, and 159, with a mean of 118.4. The 10.7-centimeter flux was 145.2, 139.1, 140.4, 144.6, 154.5, 166.1, and 155.5, with a mean of 149.3. Estimated planetary A indices were 18, 7, 7, 16, 30, 49, and 16, with a mean of 20.4. Middle latitude A index was 13, 7, 5, 14, 21, 38, and 15, with a mean of 18.1.