ARRL

ARRL Propagation Bulletin ARLP022 (2002)

SB PROP @ ARL $ARLP022
ARLP022 Propagation de K7VVV

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.
NNNN
/EX