Solar activity bounced back this reporting week, September 8 – 14, when the average daily sunspot number jumped from 68 to 92.7, and the average solar flux from 125.8 to 141.3.
Fewer Coronal Mass Ejections (CMEs) and flares were evident, with the average planetary A index declining from 24.6 to 10.7, and the 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. The 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 2 years ago, there were no sunspots at all. The average daily solar flux was only 69.7, over 56 points lower than this week, demonstrating the continued progress of Cycle 25.
The latest (Wednesday) forecast from the space weather folks at Offutt Air Force Base shows predicted solar flux peaking at 150 on October 9, and flux values on September 15 at 140. Then 135 on September 16 – 18; 130 on September 19 – 21; 120 on September 22 – 29; 125 on September 30 through October 6; 130 on October 7 – 8; 150, 148, 143, and 140 on October 9 – 12; 136, 130, 125, and 120 on October 13 – 16, and 125 on October 17.
Predicted planetary A index shows moderate levels of geomagnetic activity until October 1 – 2. The forecast is 5, 15, 18, and 12 on September 15 – 18; 5 on September 19 – 22; 12 and 10 on September 23 – 24; 14 on September 25 – 27; 8 on September 28 – 29; 22, 50, 40, 20, and 12 on September 30 through October 4; 15, 12, 10, 8, and 5 on October 5 – 9; 10, 8, 5, 15, 20, and 12 on October 10 – 15, and 5 on October 16 – 19.
Below is a nice solar video from last month:
Here is NOAA’s latest forecast discussion:
https://www.swpc.noaa.gov/products/forecast-discussion
Sunspot numbers for September 8 – 14 were 75, 72, 122, 113, 117, 93, and 57, with a mean of 92.7. The 10.7-centimeter 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. The middle latitude A index was 17, 14, 10, 9, 9, 5, and 10, with a mean of 10.6.
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