The K7RA Solar Update
Tad Cook, K7RA, of Seattle, Washington, reports for this week’s ARRL Propagation Bulletin:
No new sunspots appeared over the past reporting week, November 24 – 30. But sunspots were visible every day.
Sunspot numbers and solar flux declined, with the average daily sunspot number dropping from 66 to 46, and average daily solar flux from 116.5 to 108.3.
Solar wind streams from coronal holes kept geomagnetic indicators active, with average daily planetary A index jumping from 5.1 to 18.6, and middle latitude A index from 3.4 to 14.
On Wednesday, November 30, the magnetometer at Fairbanks, Alaska, showed the college A index at 54, which is the highest value over the past month. No doubt this produced aurora.
The current prediction from Wednesday night has solar flux reaching a peak of 130 on December 12, rather than the 135 recently predicted.
Look for flux values of 115, 115, and 120 on December 1 – 3; 125 on December 4 – 10; 130, 115, and 110 on December 11 – 13; 105 on December 14 – 17; 100 on December 18 – 23; 95, 105, and 110 on December 24 – 26; 115 on December 27 – 30, and 120 on December 31.
The planetary A index prediction is 25, 20, 10, 12, and 8 on December 1 – 5; 5 on December 6 – 7; 8 on December 8 – 9; 5 on December 10 – 16; 10 on December 17 – 18; 5 on December 19 – 21; 20, 15, 12, and 10 on December 22 – 25; and 15, 18, 10, 18, and 10 on December 26 – 30.
Solar wind news:
Sunspot numbers for November 24 through 30 were 61, 55, 60, 56, 52, 25, and 12, with a mean of 46. The 10.7-centimeter flux was 109.7, 108.5, 107.1, 107.2, 107, 107.9, and 111, with a mean of 108.3. Estimated planetary A indices were 6, 20, 16, 15, 24, 25, and 24, with a mean of 18.6. Middle latitude A index was 6, 15, 12, 10, 18, 20, and 17, with a mean of 14.
Send your tips, questions, or comments to k7ra@arrl.net.
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.
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