Solar indices pulled back this week, when average sunspot number was 25.3 for the May 19-25 period, down 38.8 points from the previous week’s average of 64.1.

Likewise, average daily solar flux over the same period was 97, down 3.4 points from the previous week’s average of 100.4.

Planetary A index average was 7.1, down 2.8 points from 9.9, and average daily mid-latitude A index was 7, down 3.9 points from 10.9.

We should continue to see this overall decline in solar activity for at least the next four years.  Compared to past cycles, this one is considerably weaker. But I wouldn’t worry much about some reports in the media suggesting we face several future solar cycles that would be very weak. Although astrophysicists know much more about the Sun than in the past, and have far better tools and resources for monitoring day-to-day activity, the record so far shows that long range forecasts have varied all over the place, and have not proved consistent or true.

Remember Mausumi Dikpati? She was the scientist who predicted that the current solar cycle (24) would be huge and record breaking, at least compared to the previous four solar cycles. It did not turn out the way we hoped. We might consider the same for more pessimistic forecasts in popular news media.

Some links concerning Ms Dikpati and her forecast:

http://www.hao.ucar.edu/Public/about/Staff/dikpati/

http://www.hao.ucar.edu/Public/about/Staff/dikpati/CV.html

https://en.wikipedia.org/wiki/Mausumi_Dikpati


The latest forecast from NOAA/USAF shows solar flux at 90 and 85 on May 27-28, 90 on May 29-30, 85 on May 31 through June 2, 90 on June 3-7, 95 on June 8, 100 on June 9-10, 95 on June 11-12, 90 on June 13-16, 85 on June 17-20, 90 on June 21-25 (except 85 on June 23), 95 on June 26-30 and 90 on July 1-4.

The latest prediction for planetary A index is 12, 8, 14, 20 and 12 on May 27-31, then 5, 8, 15, 35, 30 and 15 on June 1-6, 5 on June 7-10, 12 on June 11-13, 8 on June 14-15, then 5, 15, 12, and 10 on June 16-19, 5 on June 20-21, then 12, 10, 8, 5, 15, 12 and 8 on June 22-28, 15 on June 29-30, then 35, 30 and 15 on July 1-3, and 5 on July 4-7.

Petr Kolman, OK1MGW, from the Czech Propagation Interest Group sent us his geomagnetic forecast a day early this week.

Geomagnetic activity forecast for the period May 27-June 22, 2016

Geomagnetic field will be:
Quiet on June 19-20
Mostly quiet on May 31, June 7-8, 21
Quiet to unsettled on May 27, 30, June 9-10, 14-16, 18, 22
Quiet to active on May 28-29, June 1-3, 6, 11-13, 17
Active to disturbed on May (28-29), June 4-5

Increases in solar wind from coronal holes are expected:
on May 28-29, June 1-6, 10-13, 17-18

Parenthesis means lower probability of activity enhancement.


Here are a couple of articles about a giant sunspot last week and about changes in Earth’s magnetic field:

http://www.siue.edu/news/2016/05/Sunspot.shtml

http://bit.ly/1WZI86g


N8II sent this report on Wednesday, May 25:

“There was a good Asian opening on 20 meter CW this AM. I heard XV9NPS about S5, worked BX2AK S2-5 and worked a JA who was S8 – all well past the usual peak of propagation around 1300Z today.”


Douglas Moore sent this article from Science Daily about researchers in the Antarctic discovering new facets of space weather: https://www.sciencedaily.com/releases/2016/05/160520124427.htm



For more information concerning radio propagation, see the ARRL Technical Information Service at http://arrl.org/propagation-of-rf-signals. For an explanation of the numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere. An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/.

Monthly propagation charts between four USA regions and twelve overseas locations are at http://arrl.org/propagation.

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Sunspot numbers for May 19 through 25 were 38, 43, 17, 15, 13, 24, and 27, with a mean of 25.3. 10.7 cm flux was 98.8, 99.5, 97.8, 97.4, 97.4, 94.3, and 93.6, with a mean of 97. Estimated planetary A indices were 8, 6, 15, 7, 5, 6, and 3, with a mean of 7.1. Estimated mid-latitude A indices were 8, 6, 16, 5, 4, 6, and 4 with a mean of 7.