QST de W1AW
Propagation Forecast Bulletin 48 ARLP048
From Tad Cook, K7VVV
Seattle, WA December 1, 2000
To all radio amateurs
SB PROP ARL ARLP048
ARLP048 Propagation de K7VVV
This week we are back with the solar flux, sunspot and A index data from the past two weeks. Average solar flux rose almost 25 points two weeks ago from the previous week and then nearly another 23 points last week. Solar flux probably peaked around November 23 at 205.3. It has recently dropped below 190, and the predicted solar flux for Friday through Monday is 190, 185, 180 and 180. Geomagnetic conditions are expected to remain stable over the next week, barring some unforeseen solar flare or coronal hole. Sunspot group 9246 has quadrupled in size since Tuesday, and if magnetic fields above this rapidly growing active region become more complex, we could see some more geomagnetic disruptions if the energy is directed toward earth.
Earlier this week conditions were quite disrupted. The planetary A index on November 27-29 was 38, 37 and 52, and in the higher latitudes the College A index was 51, 65 and 62. There were some spectacular auroral effects, and some great pictures are at http://www.spaceweather.com/aurora/gallery_26nov00.html.
W5RYA operated from Northeast Texas last weekend during the DX contest, and he reported that on the higher bands, all Northern European and Asiatic Russian stations had a raspy buzz-like quality to their signals. I would imagine this was on Sunday, when the high latitude College K index was as high as 6. This is consistent with the distortion from aurora. He also reported some echoey signals and some severe fading on Sunday.
Solar flux is expected to drop down to 145 from December 8-13, then rise to a peak near 200 around December 23-25. Conditions should be good for the ARRL 160 Meter Contest this weekend as well as the TOPS 80 Meter CW Contest. It is still too early to tell, but the 10 Meter contest next weekend is during a time when the solar flux may be low and there could be some higher geomagnetic activity due to recurring coronal holes. Check back next week.
Sunspot numbers for November 16 through 22 were 142, 140, 171, 174, 168, 160 and 136 with a mean of 155.9. 10.7 cm flux was 154.2, 163.3, 177.1, 174.9, 173.7, 185.4 and 194.9, with a mean of 174.8, and estimated planetary A indices were 4, 4, 6, 7, 9, 9 and 7 with a mean of 6.6.
Sunspot numbers for November 23 through 29 were 141, 134, 110, 95, 121, 154 and 160 with a mean of 130.7. 10.7 cm flux was 205.3, 197.1, 202, 202.4, 191.7, 195.5 and 188.4, with a mean of 197.5, and estimated planetary A indices were 7, 9, 7, 22, 38, 37 and 52 with a mean of 24.6.