ARRL

ARRL Propagation Bulletin ARLP022 (2001)

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 25, 2001
To all radio amateurs 

SB PROP ARL ARLP022
ARLP022 Propagation de K7VVV

Geomagnetic conditions were quieter this week, and solar flux and
sunspot numbers were a little higher. Average solar flux was up
nearly 10 points and average sunspot numbers were up by about 7.
Last Saturday had unsettled to active geomagnetic conditions, with
both the planetary and mid-latitude K indices at 4 over two of the
eight three-hour reporting periods, but the planetary A index for
the day was only 12.

Solar flux is expected to peak over the next week. Solar flux for
Friday is predicted at 165, and then 170 for Saturday through
Tuesday. The predicted planetary A index for Friday through Monday
is 8, 10, 20 and 12. The earth is currently inside a solar wind
stream flowing from a coronal hole. Sunspot 9463 is rapidly growing
at the center of the disk, and holds the greatest chance of emitting
solar flares. A holographic image of the far side of the sun shows
no substantial sunspots that might rotate into view in the next
couple of weeks.

This weekend HF contesters will be enjoying the CQ Worldwide WPX CW
Contest. Conditions should be good on Saturday, but may get rough on
Sunday with higher geomagnetic activity.

Sunspot numbers for May 17 through 23 were 137, 109, 92, 99, 118,
159 and 192 with a mean of 129.4. 10.7 cm flux was 147.4, 138.2,
141.3, 141.5, 150.1, 152 and 158.7, with a mean of 147, and
estimated planetary A indices were 9, 11, 12, 10, 8, 9 and 11 with a
mean of 10.
NNNN
/EX