QST de W1AW
Propagation Forecast Bulletin 23 ARLP023
From Tad Cook, K7VVV
Seattle, WA June 1, 2001
To all radio amateurs
SB PROP ARL ARLP023
ARLP023 Propagation de K7VVV
Average daily sunspot numbers rose nearly 28 points and average solar flux increased slightly over the past week. Solar flux peaked on Thursday, May 24 at 170.3 and has been declining since. Solar flux for Friday and Saturday should be around 130, and 125 for Sunday and Monday. Flux values are expected to rise very gradually, reaching 140 around June 8, 145 around June 11, and 150 around June 14. This is based on the recent solar rotation, and is blind to any new activity that may emerge.
Last week's prediction that solar flux would peak over the weekend was off. Instead it had peaked on the Thursday when the bulletin was written. A geomagnetic disturbance forecast for Sunday was only brief but came up again on Monday when the planetary K index was four during several periods. WA8OLD reported from Upper Michigan that Sunday had the best 15 meter propagation he had seen in a long time. He worked the world with low power and an inverted V. Also, KB9NXD wrote to remind us that http://sec.noaa.gov/ftpdir/latest/wwv.txt gives the text of the WWV solar indices broadcast. It you miss it on the air at 18 minutes after the hour, you can also hear it repeated anytime at 303-497-3235. Every three hours the K index is revised, and this is a good indication of geomagnetic stability and general conditions. When the K index is below three, HF propagation is often quite good. When it is above three, watch out!
Since May is at an end, now is the time to review some monthly sunspot and solar flux averages. Average daily sunspot numbers for January through May were 142.7, 131, 166.7, 163.6 and 135.1. Average daily solar flux values for the same period were 166.6, 147.2, 177.7, 178.2 and 148.8. March and April's averages were greatly affected by the huge rise in solar activity around the transition from March to April.
Here are some path projections from WA8OLD in Sault Ste Marie, Michigan. This should also be good for Ontario.
Sunspot numbers for May 24 through 30 were 171, 146, 167, 189, 190, 131 and 105 with a mean of 157. 10.7 cm flux was 170.3, 161.9, 147.4, 146.9, 143, 138.5 and 132.3, with a mean of 148.6, and estimated planetary A indices were 9, 8, 8, 9, 18, 10 and 5 with a mean of 9.6.