ZCZC AP22
QST de W1AW
Propagation Forecast Bulletin 22 ARLP022
From Tad Cook, K7VVV
Seattle, WA May 31, 2002
To all radio amateurs
SB PROP ARL ARLP022
ARLP022 Propagation de K7VVV
Average daily solar flux and sunspot numbers rose this week. Compared to last week (the reporting week for this bulletin is Thursday through Wednesday) average daily sunspot numbers were up nearly 65 points and daily solar flux was up by 15. There were some very active geomagnetic days. Monday, May 27 was quite active with the planetary A index at 28, and Thursday, May 23 was very stormy with an A index of 54. Thursday's problems were probably from several coronal mass ejections the day before.
Solar flux is expected to fade a bit this week, and may reach a short-term minimum around Monday or Tuesday.
There is a new large sunspot on the southeast limb of the sun. Region 9973 could bring solar flares.
We're moving out of spring propagation and toward summer conditions. 10-meters is going out of season, and moving into summer will see lower MUF, affecting propagation on 15-meters. 17 and 20-meters will be the best summertime bands for HF DX, with 20-meters offering the best conditions right after sunrise or into the evening, rather than mid day.
Sunspot numbers for May 23 through 29 were 229, 242, 221, 232, 227, 218, and 206, with a mean of 225. 10.7 cm flux was 180.3, 189.1, 182.6, 183.1, 186.7, 186.4, and 184.8, with a mean of 184.7. Estimated planetary A indices were 54, 7, 6, 10, 28, 12, and 12, with a mean of 18.4.