ZCZC AP49
QST de W1AW
Propagation Forecast Bulletin 49 ARLP049
From Tad Cook, K7VVV
Seattle, WA December 5, 1997
To all radio amateurs
SB PROP ARL ARLP049 ARLP049 Propagation de K7VVV
HF conditions were good over the past week, with geomagnetic indices very stable. Most periods had a K index of zero or one, which is very quiet. Quiet conditions would be very good for the 160 meter contest this weekend, but geomagnetic indices may be up just slightly. Currently the Boulder A index is forecast to be eight on both Saturday and Sunday, which indicates slightly more geomagnetic activity than we have seen recently.
Solar flux was up, with the average for the week increasing by over 13 points compared to the week previous. Average solar flux for the past 90 days increased by another point this week to 94, and the flux was well above this level on every day, which is a nice upward trend. Speaking of upward trends, both the average solar flux and the average sunspot number for the same period one year ago were over 30 points lower.
Watch for solar flux to drop a bit below 100 over the next few days, then rise above 100 again a few days before Christmas and above 110 a day or two after the holiday. Geomagnetic conditions might become a bit unsettled around December 19 or 20. Predicted solar flux for December 5 to 7 is 105, 103 and 101.
Sunspot Numbers for November 27 through December 3 were 44, 40, 48, 56, 73, 54 and 54 with a mean of 52.7. 10.7 cm flux was 111.1, 116.3, 112.1, 112.4, 117, 112.2 and 112.2, with a mean of 113.3, and estimated planetary A indices were 2, 2, 2, 4, 3, 3, and 6, with a mean of 3.1.