Tad Cook, K7RA, Seattle, reports: Two new sunspot groups emerged on January 9 and another showed up on January 12. Average daily sunspot numbers rose six points this week to 42.4, and average daily solar flux increased from 91.4 to 101.6.
Geomagnetic indicators were quieter, with average daily planetary A index declining from 7.7 to 6.1, and average daily middle latitude A index from 6 to 4.1.
The higher A index values on January 8 and 9 were from a G-1 class storm caused by co-rotating interaction regions.
Predicted solar flux for the next month shows values peaking at 120 on January 21 – 24 and again around mid-February. Predicted values are 104 and 106 on January 13 – 14; 108 on January 15 – 17; 106 on January 18 – 20; 120 on January 21 – 24; 110 on January 25; 100 on January 26 – 27; 95 and 90 on January 28 – 29; 85 on January 30 – February 1; 95 and 105 on February 2 – 3; 100 on February 4 – 5; 102 on February 6 – 7; 105 on February 8; 110 on February 9 – 10; 115 on February 11 – 12, and 120 on February 13 – 20.
Predicted planetary A index is 5 on January 13 – 14;14, 24, 12, and 8 on January 15 – 18; 5 on January 19 – 22; 10 on January 23; 8 on January 24 – 26; 5 on January 27; 10 on January 28 – 30; 5 on January 31 – February 3; 15, 10, and 8 on February 4 – 6; 5 on February 7 – 11; 12, 10, and 8 on February 12 – 14, and 5 on February 15 – 18.
Sunspot numbers for January 6 through 12 were 35, 38, 31, 36, 38, 51, and 68, with a mean of 42.4. The 10.7-centimeter flux was 93.7, 107.3, 102.4, 102.1, 102.2, 100, and 103.2, with a mean of 101.6. Estimated planetary A indices were 2, 2, 14, 10, 6, 5, and 4, with a mean of 6.1. Middle latitude A index was 2, 1, 9, 7, 4, 3, and 3, with a mean of 4.1.
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.