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.