QST de W1AW
Propagation Forecast Bulletin 46 ARLP046
From Tad Cook, K7VVV
Seattle, WA November 17, 2000
To all radio amateurs
SB PROP ARL ARLP046
ARLP046 Propagation de K7VVV
Sunspot numbers and solar flux were down over the past week. Average sunspot numbers were down over 40 points and average solar flux was off by 36 points relative to the previous week. The expected geomagnetic disturbance arrived earlier than predicted, with Friday being the worst day, with a planetary A index of 41. Planetary K indices reached 6 for several periods on Friday. Saturday was fairly quiet, and Sunday was fairly active with the planetary K index at 20. Following the weekend the geomagnetic conditions have been quiet.
Solar flux probably reached a short term minimum of 143.7 on Monday, and is now rising. Flux values for Friday through Tuesday are expected to be 155, 155, 160, 160 and 165. Solar flux is expected to peak around 200 from November 27-29. Expected planetary A index values for Friday through Tuesday are 12, 10, 20, 12 and 10, so the current predicted value for this Sunday is nearly identical to last Sunday. The unsettled conditions on Sunday will probably be due to a solar flare that occurred early Thursday.
Beyond the weekend, the next predicted unsettled day is November 29, and December 5 looks like an active geomagnetic day, as well as December 8 and 9. Of course this is based upon the previous solar rotation.
Look at the chart at http://www.wm7d.net/hamradio/solar/. It looks as if solar flux and sunspots generally declined over the past six months.
Sunspot numbers for November 9 through 15 were 149, 141, 128, 112, 99, 131 and 144 with a mean of 129.1. 10.7 cm flux was 166.2, 153.4, 149.6, 146.6, 143.7, 148.6 and 146.5, with a mean of 150.7, and estimated planetary A indices were 11, 41, 12, 21, 8, 5 and 5 with a mean of 14.7.