ARRL

ARRL Propagation Bulletin ARLP009 (2001)

SB PROP @ ARL $ARLP009
ARLP009 Propagation de K7VVV

ZCZC AP09
QST de W1AW  
Propagation Forecast Bulletin 9  ARLP009
From Tad Cook, K7VVV
Seattle, WA  March 2, 2001
To all radio amateurs 

SB PROP ARL ARLP009
ARLP009 Propagation de K7VVV

Greetings from Seattle, where we just lived through an exciting
earthquake on Wednesday. No damage at K7VVV, but it has had everyone
a bit rattled.

Average sunspot numbers were lower last week, but average solar flux
was about the same, when compared to the previous week. Sunspot
numbers were down to 88 on Wednesday, the lowest since January 17.
Average daily solar flux for the months of December, January and
February were 173.6, 166.6 and 147.2, indicating a decline in
activity. Average sunspots over the same period were 146, 143 and
131. A glance at the charts at
http://www.wm7d.net/hamradio/solar/past_cycle.shtml shows the
decline, with recent numbers looking like 1999, before last year's
peak.

The next short term peak in activity is expected around March 8,
with a solar flux of 155. Predicted flux values for the next few
days, Friday through Monday, are 135, 140, 145 and 150. Moderate
geomagnetic conditions are expected for the ARRL International DX
Phone Contest this weekend, with a planetary A index of 12 on
Saturday and 10 on Sunday. However, this is an estimate based on the
80% chance that a full halo coronal mass ejection from the sun on
Thursday will not have a large effect on the earth. If it is felt,
it should be on Saturday, and there is a small possibility of
aurora.

We are moving toward spring conditions, which means better DX
openings between the northern and southern hemispheres. Watch for
the upper HF spectrum to open toward the east and south early in the
day, then peak north and south in mid day, and then toward the west
and south toward the evening.

Sunspot numbers for February 22 through 28 were 135, 135, 99, 111,
91, 90 and 88 with a mean of 107. 10.7 cm flux was 145.8, 145.2,
137.3, 134.9, 135.4, 130.6 and 131.8, with a mean of 137.3, and
estimated planetary A indices were 6, 11, 5, 3, 10, 13 and 7 with a
mean of 7.9.
NNNN
/EX