The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: Over the December 7-13 reporting week, we saw 3 days with zero sunspots — December 8, 9, and 13. Compared with the previous 7 days, average daily sunspot numbers more than doubled to 6.9, and average daily solar flux increased from 69.6 to 71. One new sunspot group (2691) emerged on December 10 with one spot, which increased to three over the next 2 days, but by December 13, it had disappeared.

Geomagnetic numbers were low, with the average planetary A index declining from 11.6 to 7.4, and the mid-latitude A index from 8.1 to 5.6.

The latest forecast from the USAF and NOAA shows solar flux at 72 on December 14-16; 74 on December 17-23; 72 on December 24-26; 70 on December 27-January 5; 72 on January 6-8; 74 on January 9-19; 72 on January 20-22, and 70 on January 23-27.

Predicted planetary A index is 5 on December 14-15; 12, 20, 18, and 10 on December 16-19; 8 on December 20-21; 5 on December 22-26; 12 and 8 on December 27-28; 5 on December 29-30; 10, 26, 14, and 10 on December 31-January 3; 5 on January 4-6; 14, 16, 14, and 8 on January 7-10; 5 on January 11-12; 8, 25, 10, 8, and 8 on January 13-17; 5 on January 18-22, and 12, 8, 5, 5, and 10 on January 23-27.

ARRL News Letter on December 14, 2017