Tad Cook, K7RA, Seattle, Washington, reports:
There was some evidence of sporadic-E propagation this week on 6 and 10 meters, which is always surprising and exciting.
Solar activity was the same as last week, at least going by the numbers.
Average daily sunspot numbers rose slightly from 68.6 to 74.4, while average daily solar flux only budged from 120 to 120.3.
Geomagnetic indicators were quieter, with average daily planetary A index shifting from 10.7 to 5, and average middle latitude numbers from 9.3 to 4.6. We listed the middle latitude A index on May 6 as 2, but that number is an estimate. At the end of that day, the last K index reading was not reported, and since the A index for the day is calculated from all the K index readings, there was not any official middle latitude A index reported and was estimated on available data.
Thursday’s outlook for solar flux is more optimistic than last week’s prediction, with no values below 100. Expected flux values are 124 on May 12 – 13; 126 on May 14 – 16; 124 on May 17 – 18; 118 on May 19 – 21; 120, 124, and 121 on May 22 – 24; 118 on May 25 – 27; 116 on May 28 – 31; 118 on June 1 – 5; 116 and 118 on June 6 -7; 120 on June 8 – 9; 122 on June 10 – 14, and 118 on June 15 – 17.
Planetary A index is predicted at 6, 8, 12, 8, 14, and 8 on May 12 – 17; 5 on May 18 -19; 12 and 8 on May 20 – 21; 5 on May 22 – 23; 18 on May 24; 15 on May 25 – 27; 8 on May 28, and 5 on May 29 through June 15. There will be a nice long quiet spell of more than 2 weeks.
Wednesday’s forecast was prepared by the US Air Force personnel.
Sunspot
numbers for May 5 through 11 were 85, 64, 66, 89, 71, 62, and 84, with a mean
of 74.4. The 10.7-centimeter flux was 119.9, 119.2, 118.1, 119.2, 117, 115.8,
and 132.9, with a mean of 120.3. Estimated planetary A indices were 4, 5, 3, 6,
8, 3, and 6, with a mean of 5. Middle latitude A index was 4, 2, 4, 7, 8, 2,
and 5, with a mean of 4.6.
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.
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