SB PROP @ ARL $ARLP022
ARLP022 Propagation de K7RA
ZCZC AP22
QST de W1AW
Propagation Forecast Bulletin 22 ARLP022
From Tad Cook, K7RA
Seattle, WA May 27, 2016
To all radio amateurs
SB PROP ARL ARLP022
ARLP022 Propagation de K7RA
Solar indices pulled back this week, when average sunspot number was
25.3 for the May 19 to 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 Dikpatu 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 and 28, 90 on May 29 and 30, 85 on May 31 to June 2, 90 on
June 3 to 7, 95 on June 8, 100 on June 9 and 10, 95 on June 11 and
12, 90 on June 13 to 16, 85 on June 17 to 20, 90 on June 21 to 25
(except 85 on June 23), 95 on June 26 to 30 and 90 on July 1 to 4.
The latest prediction for planetary A index is 12, 8, 14, 20 and 12
on May 27 to 31, then 5, 8, 15, 35, 30 and 15 on June 1 to 6, 5 on
June 7 to 10, 12 on June 11 to 13, 8 on June 14 and 15, then 5, 15,
12, and 10 on June 16 to 19, 5 on June 20 and 21, then 12, 10, 8, 5,
15, 12 and 8 on June 22 to 28, 15 on June 29 and 30, then 35, 30 and
15 on July 1 to 3, and 5 on July 4 to 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 to June 22, 2016
Geomagnetic field will be: Quiet on June 19 and 20 Mostly quiet on
May 31, June 7 and 8, 21 Quiet to unsettled on May 27, 30, June 9
and 10, 14 to 16, 18, 22 Quiet to active on May 28 and 29, June 1 to
3, 6, 11 to 13, 17 Active to disturbed on (May 28 and 29), June 4
and 5
Increases in solar wind from coronal holes are expected on May 28
and 29, June 1 to 6, 10 to 13, 17 and 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 CW this AM, heard XV9NPS about
S5, worked BX2AK S 2-5 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.
Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins.
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.
NNNN
/EX
