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.

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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.

Like last week, eight new sunspot groups emerged this reporting week, September 7 – 13, 2023.

One appeared on September 7, another on September 9, four more on

September 10, another on September 11, and one more on September 12.

Solar activity made a nice comeback, with average daily sunspot numbers rising from 95.4 to 138.1, and solar flux increasing from 137.6 to 159.9.

The most active geomagnetic day was September 12, when the planetary A index was 25. A “stealth CME” with an aurora visible as far south as Missouri was reported on spaceweather.com.

The average daily planetary A index decreased from 15.4 to 10.4, and middle latitude numbers decreased from 16.3 to 11.3.

The autumnal equinox in the Northern Hemisphere is on September 22 — just a week away.

It seems that the next sustained short-term peak in solar flux is a few weeks off, with values between 150 and 155 on October 12 – 17, although it’s expected to reach 150 on September 23 – 24.

The forecast shows the solar flux at 145, 145, 148, 145, and 145 on September 14 – 18; 148 on September 19 – 20; 145 on September 21 – 22; 150 on September 23 – 24; 145 on September 25; 140 on September 26 – 27; 135 on September 28 – 30; 130, 135, 130, and 135 on October 1 – 4; 140 on October 5 – 6, and 135 on October 7 – 8.

Predicted planetary A index is 12 and 15 on September 14 – 15; 8 on September 16 – 17; 5, 5, and 10 on September 18 – 20; 5, 5, and 12 on September 21 – 23; 5 on September 24 – 27; 8, 12, and 8 on September 28 – 30, and 5 on October 1 – 8. Sunspot numbers for September 7 – 13, 2023, were 135, 123, 119, 167, 173, 141, and 109, with a mean of 138.1. The 10.7-centimeter flux was 160.8, 160.9, 161.4, 163.9, 176.4, 153.5, and 142.6, with a mean of 159.9. Estimated planetary A indices were 6, 6, 8, 4, 7, 25, and 17, with a mean of 10.4. The middle latitude A index was 11, 8, 12, 6, 8, 17, and 17, with a mean of 11.3.

Seven new sunspots emerged this week: one on September 2, two on September 3, two more on September 4, one on September 5, and one on September 6.

The average daily sunspot number was up from 78.7 to 95.4, while the average daily solar flux decreased from 140.9 to 137.6.

Geomagnetic activity was higher. On September 2, the planetary A index was 38 when Earth moved through a high-speed solar wind. In Alaska, the college A index at Fairbanks was 59.

The average daily planetary A index increased from 7 to 15.4, and the average middle latitude A index rose from 8.9 to 16.3.

Predicted solar flux is 150, 155, 155, and 150 on September 7 – 10; 140 on September 11 – 13; 145, 150, 150, and 155 on September 14 – 17; 150, 155, and 150 on September 18 – 20; 145 on September 21 – 22; 150 on September 23 – 24; 145 on September 25; 140 on September 26 – 27; 135 on September 28 – 30; 130, 135, 130, and 135 on October 1 – 4, and 140 on October 5 – 6.

Predicted planetary A index is 12, 10, 5, and 5 on September 7 – 10; 8 on September 11 – 13; 10, 8, 12, 8, and 8 on September 14 – 18; 5 on September 19 – 22; 12 on September 23; 5 on September 24 – 27; 8, 12, 5, and 12 on September 28 through October 1; 12, 10, 12, and 10 on October 2 – 5, and 5 on October 6 – 10.

I observed some interesting 12-meter propagation via PSK Reporter while using FT8 at 1745 UTC on September 4. My signal was received only over a narrow, 300-mile band hugging the east coast from Maine to Florida. The signals were between 2,200 – 2,500 miles away, and nowhere else.

Three hours later, at 2045 UTC, the reception reports along the coast expanded to 600 miles, and then 2,000 – 2,600 miles.

Later, at 2300 UTC, there was the same pattern, but it was a 200-mile band spanning 2,300 – 2,500 miles wide.

The next day, at 1700 UTC, there was an arc from Virginia to south Texas stretching 1,700 – 2,300 miles wide. At 1715 UTC, it drifted to a coverage of 1,750 – 2,600 miles.

Before FT8 and PSK Reporter, there was no practical way to observe propagation. Sunspot numbers for August 31 through September 6, 2023, were 77, 83, 77, 79, 100, 121, and 131, with a mean of 95.4. The 10.7-centimeter flux was 139.9, 135.8, 131.2, 130.5, 136, 142.9, and 147.1, with a mean of 137.6. Estimated planetary A indices were 6, 12, 38, 25, 8, 11, and 8, with a mean of 15.4. Middle latitude A index was 8, 15, 25, 28, 14, 14, and 10, with a mean of 16.3.

Solar activity was down again this week, with average daily sunspot numbers dropping from 105.9 to 78.7, and the average daily solar flux dropping from 149.4 to 140.9. Only three sunspot groups appeared, occurring on August 25, 28, and 30.

There has been a gradual transition from summer to fall conditions, with 10 and 12 meters opening more frequently. The autumnal equinox is only 3 weeks away.

Geomagnetic indicators were a little lower. The average planetary A index went from 8.4 to 7, and average middle latitude numbers went from 10.1 to 8.9.

Predicted solar flux shows a peak around 168 on September 18 – 21.

Forecast values are 145 on August 31 through September 1; 150, 150, and 145 on September 2 – 4; 150 on September 5 – 6; 156 on September 7 – 8; 150 on September 9; 147 on September 10 – 11; 145, 150, 155, 150, 155, and 160 on September 12 – 17; 168 on September 18 – 21; 165, 160, and 148 on September 22 – 24; 150 on September 25 – 26, and 152, 150, 145, and 140 on September 27 – 30.

Predicted planetary A index is 5, 10, and 10 on August 31 through September 2; 5 on September 3 – 6; 8 on September 7 – 8; 5 on September 9 – 13; 12, 10, 10, and 8 on September 14 – 17; 5 on September 18 – 22; 10, 10, and 8 on September 23 – 25, and 5 on September 26 to October 2.

Read about India’s solar mission at https://bit.ly/3PiPJ1N.

Check out a video about solar flares at https://bit.ly/47X6gzC. Sunspot numbers for August 24 through 30, 2023, were 86, 77, 75, 69, 68, 82, and 94, with a mean of 78.7. The 10.7-centimeter flux was 144.1, 138.9, 139.3, 141.5, 141.7, 142.2, and 138.6, with a mean of 140.9. Estimated planetary A indices were 9, 5, 7, 11, 6, 5, and 6, with a mean of 7. The middle latitude A index was 9, 7, 9, 13, 8, 7, and 9, with a mean of 8.9.