QST de W1AW
Propagation Forecast Bulletin 8 ARLP008
From Tad Cook, K7VVV
Seattle, WA February 22, 2002
To all radio amateurs
SB PROP ARL ARLP008
ARLP008 Propagation de K7VVV
Average daily sunspot numbers and solar flux were both down this week. Fortunately, geomagnetic indices were low as well. The average daily planetary A index dropped from 10 to 6. This contrasts with last week's warning of possible geomagnetic activity for the weekend, although the bulletin did hedge a bit, stating effects could miss earth and conditions turn out mild, which they did. The result was very good conditions for the contest weekend.
Last week's bulletin suggested a rising solar flux toward the 240-245 level around February 24-28, but the latest projection shows flux values around 200 for the next few days, gradually declining toward 180 around March 6. There isn't much visible sunspot activity, and holographic images show nothing substantial on the sun's far side.
Geomagnetic conditions could become unstable by Saturday with a planetary A index around 20. This is because of a coronal mass ejection that left the sun on February 20, erupting from sunspot 9825. This area is right at the northwestern edge of the visible solar disk, so any effect on earth is uncertain.
Check out this interesting set of links from the Solar Physics Department at the Royal Observatory of Belgium. The URL is http://sidc.oma.be/html/ClickMaps.html, and the department's home page is http://sol.oma.be/homepage.php3.
Sunspot numbers for February 14 through 20 were 209, 156, 134, 121, 103, 130 and 157 with a mean of 144.3. 10.7 cm flux was 196.1, 195, 193.5, 196.6, 192.8, 189.4 and 193.4, with a mean of 193.8, and estimated planetary A indices were 4, 4, 5, 8, 9, 4 and 8 with a mean of 6.