ZCZC AP52
QST de W1AW
Propagation Forecast Bulletin 52 ARLP052
From Tad Cook, K7VVV
Seattle, WA December 27, 1997
To all radio amateurs
SB PROP ARL ARLP052
ARLP052 Propagation de K7VVV
Sunspot numbers were down a little last week, while average solar flux was up about five points. Recently the average solar flux for the previous ninety days had dropped one point from 94 to 93 after many months of steadily rising, but last week it rose to 94 again. Solar flux rose above this value for the last three days of the week. Geomagnetic activity has been very stable, indicating good conditions. Solar flux is expected to peak over this weekend around 104, then drop to 102 by Monday, then drop below 100 next week, below 90 by January 6, and above 90 again around the middle of the month. No geomagnetic disturbances are forecast, although January 6 and 7 could have slightly more active conditions.
For the last bulletin of 1997 an assessment is due, as well as a look forward into 1998.
A year ago the average solar flux for the first 24 days of December was 78.8. This month the average for the same 24 calender days is 97.6, nearly a 19 point gain. The current NOAA SESC prediction for smoothed 10.7 cm flux is predicted to increase about 30 points over the next six months and over 50 points or more a year from now. Look for better conditions in 1998 as cycle 23 really gets going. 10 and 12 meters should finally open on a regular basis, with excellent conditions by next Fall.
Sunspot Numbers for December 18 through 24 were 35, 16, 27, 30, 41, 72 and 67 with a mean of 41.1. 10.7 cm flux was 86.2, 87.7, 89.6, 92, 97, 104.1 and 107.8, with a mean of 94.9, and estimated planetary A indices were 6, 2, 2, 3, 2, 3, and 3, with a mean of 3.