QST de W1AW
Propagation Forecast Bulletin 31 ARLP031
From Tad Cook, K7VVV
Seattle, WA August 1, 1997
To all radio amateurs
SB PROP ARL ARLP031
ARLP031 Propagation de K7VVV
Solar flux has been settling down from last week, but several coronal holes have moved into position, and are probably the cause of geomagnetic upset on earth along with rising K and A indices. A coronal mass ejection on July 30 is a likely suspect as well. Look for marginal conditions this weekend as a result.
Watch for a return of the recent activity about 28 days later. Based on recent activity, solar flux is expected to stay around the low seventies.
Look for good conditions after the A and K indexes quiet down. For an updated reading tune to WWV at 18 minutes after the hour, with new K indices at 0318, 0618, 0918, 1218, 1518, 1818 and 2418 UTC. K indices below three mean stable conditions, and above three they do not. You can also get the latest WWV forecast over the phone by calling (303) 497-3235.
Sunspot Numbers for July 24 through 30 were 44, 65, 58, 53, 26, 24 and 12 with a mean of 40.3. 10.7 cm flux was 78.7, 80.4, 76.6, 74.5, 74.2, 72.7 and 71, with a mean of 75.4, and estimated planetary A indices were 10, 5, 4, 6, 5, 3, and 7, with a mean of 5.7.