ZCZC AP70
QST de W1AW
Propagation Forecast Bulletin 50 ARLP050
From Tad Cook, KT7H
Seattle, WA November 30, 1996
To all radio amateurs
SB PROP ARL ARLP050
ARLP050 Propagation de KT7H
What an exciting week for propagation. Solar activity took an unexpected leap over the past week, rising to levels not observed in over two years. We have not seen solar flux at 100 since September 3, 1994 and when it reached 104.4 on November 25, the solar flux had not been that high since February 24, 1994.
It is uncertain what this activity has to do with ushering in cycle 23, since the sunspots producing these numbers were around the Sun's equator, and new cycle regions are associated with higher latitudes.
The average flux was up more than 20 points above the previous week, while sunspot numbers were up over 35 points and the A index was down over 4 points.
The current forecast is for flux values to go below 90 around December 5, a minimum of 72 from December 7 through 16, and above 90 again after December 21. This is based on the previous solar rotation, so really anything could happen. This is merely a forecast that tries to predict what will happen when the solar regions that caused the current activity rotate into view again.
We had several comments via email during the past week. Don Stoner, W6TNS commented that current conditions don't reflect what his logbook shows for 1994. This is probably because we haven't had a sustained period of higher solar activity.
Several people, including W7LKR said that conditions on 80 meters were quite odd, with absorption up normal communications to regional stations difficult.
Readers who wish to contact the author of this bulletin can reach me via email at tad@ssc.com. For packet radio users the address is KT7H @ N7DUO.#WWA.WA.USA.NOAM.
The flux numbers given in this weekly bulletin are always the noon measurements from the Penticton, BC observatory, but there are actually three per day. Below is a table of each flux value for every day since the last bulletin:
11/21/96 1800 UTC: 74.2
11/21/96 2000 UTC: 74.4
11/21/96 2200 UTC: 75.5
11/22/96 1800 UTC: 79.5
11/22/96 2000 UTC: 82.6
11/22/96 2200 UTC: 82.3
11/23/96 2200 UTC: 95.0
11/23/96 2000 UTC: 91.0
11/23/96 1800 UTC: 90.6
11/24/96 1800 UTC: 103.5
11/24/96 2000 UTC: 99.8
11/24/96 2200 UTC: 104.2
11/25/96 1800 UTC: 103.6
11/25/96 2000 UTC: 104.4
11/25/96 2200 UTC: 102.1
11/26/96 1800 UTC: 104.0
11/26/96 2000 UTC: 103.6
11/26/96 2200 UTC: 106.1
11/27/96 1800 UTC: 99.6
11/27/96 2000 UTC: 102.7
11/27/96 2200 UTC: 100.7
11/28/96 1800 UTC: 96.1
11/28/96 2000 UTC: 98.1
11/28/96 2200 UTC: 97.5
Thanks to Cary Oler for the above data. Cary has a very interesting and informative web page with solar data and current solar images at http://holly.cc.uleth.ca/solar/index.html
Sunspot Numbers for November 21 through 27 were 26, 27, 73, 54, 89, 85 and 63, with a mean of 59.6. 10.7 cm flux was 74.4, 82.6, 91, 99.8, 104.4, 103.6 and 102.7, with a mean of 94.1. Planetary A indices for the same period were 5, 3, 3, 8, 4, 4, and 8, with a mean of 5.