ARLP021 Propagation de KT7H: May 24, 1996

Propagation Forecast Bulletin 21 ARLP021
From Tad Cook, KT7H
Seattle, WA May 24, 1996
To all radio amateurs

ARLP021 Propagation de KT7H

There were four consecutive days of zero sunspots last week. The average solar flux was down five points from the previous period. Expect similar conditions through the rest of 1996 as we experience the solar minimum.

A note from Shel Shallon, W6EL pointed out that the progress of any solar cycle is judged in terms of smoothed sunspot numbers, and that the smoothed number for a given month is an average of 13 months of data, centered on the month of interest. Therefore we won't really know when the sunspot cycle minimum has occurred until some time after the event. Shel is the author of the popular Mini Prop propagation prediction software.

Shel goes on to say: "Reports last year that the first spots from cycle 23 had been observed were erroneous. It is now believed that the first spot from cycle 23 was observed on May 10, 1996. Typically, the sunspot cycle minimum does not occur until at least twelve months following the appearance of the first spots of new cycle. Therefore, the minimum between cycles 22 and 23, and the official start of cycle 23, may not occur before May 1997".

Current solar flux progress for the short term points to a slow rise to a peak just above 70 around June 7 or 8, and then a drop below 70 around the middle of June.

For the WPX contest this weekend look for more of the same conditions; few sunspots with a quiet geomagnetic field.

Sunspot Numbers for May 16 through 22 were 26, 12, 0, 0, 0, 0 and 11, with a mean of 7. 10.7 cm flux was 71, 71.2, 70.3, 68.8, 68, 66.9 and 66, with a mean of 68.9.