‰  NOW 18 WPM transition file follows‰

For seven days from May 28 through June 3, average daily sunspot
numbers dropped from 56.1 the previous week to 34.3.  Average daily
solar flux barely changed from 97.6 to 97.8 over the same two weeks.
But both numbers show a rising trend in recent days.  Predicted
solar flux is 125 on June 5, 130 on June 6, 135 on June 7 to 11,
then 130, 120 and 110 on June 12 to 14, 100 on June 15 and 16, 95 on
June 17 to 22, 90 on June 23 to 25, 95 on June 26 to 28, 100 on June
29, then peaking at 120 on July 7 and 8 and dropping back below 100
after July 13.  Predicted planetary A index is 5, 8 and 12 on June 5
to 7 then 15, 25 and 15 on June 8 to 10, then 10, 5 and 8 on June 11
to 13, then 15 and 12 on June 14 and 15, and 5 on June 16 through
July 3, then 10, 25, 20 and 12 on July 4 to 7.  OK1HH predicts the
geomagnetic field will be quiet to unsettled June 5, quiet to active
June 6 to 9, disturbed on June 10, quiet to unsettled June 11,
mostly quiet June 12, quiet on June 13, active to disturbed June 14,
quiet to active June 15 and 16, quiet on June 17 to 21, quiet to
unsettled on June 22 to 25, quiet to active June 26, active to
disturbed June 27, quiet June 28 to 30, and mostly quiet on July 1.
OK1HH predicts increasing solar wind on June 12, June 16 and 17 and
June 27 and 28, with reduced prediction reliability during the
latter two periods.  On May 28 the daily sunspot number was 11, the
lowest non zero sunspot number possible.  This means there was just
one sunspot group visible.  There are no sunspot numbers between 1
and 10, because there is a value of 10 for each sunspot group, and a
value of 1 is added for every sunspot in the group.  The last time
the daily sunspot number was 11 was July 16, 2014 and the following
day the sunspot number was zero.  Note that this was just a few
months after the peak of cycle 24, which I reckon to be around
February and March 2014 using our three month moving average.  Look
here for a long range forecast of smoothed sunspot numbers,
//1.usa.gov/1HOVlDP .  These are International Sunspot numbers, on a
different scale from the ones we present in this bulletin.  Note it
shows the current cycle peaking in March and April 2014, just like
our 3 month moving averages of daily sunspot numbers.  Four years in
the future we see the next cycle minimum in summer 2019.  The
average centered on December 2014 through April 2015 is 107.8, 98.2,
78.1, 68.2 and 72.4, so we saw a small uptick in the latest numbers.
Now to make us all feel better, I will cherry pick data.  The
monthly sunspot averages for March, April and May 2015 were 61.7,
72.6 and 83.  No foolin.  Last week during the Seattle International
Film Festival I attended a screening of The Russian Woodpecker, a
documentary about the Soviet cold war era Duga 3 OTH HF RADAR that
plagued HF radio users all over the world during the 1970s and
1980s.  Like many of the festival films, the film maker attended the
first showing and answered audience questions afterward.  For more
information concerning radio propagation, see the ARRL Technical
Information Service at //arrl.org/propagation of rf signals.  For an
explanation of the numbers used in this bulletin, see //arrl.org/the
sun the earth the ionosphere.  An archive of past propagation
bulletins is at //arrl.org/w1aw bulletins archive propagation.  More
good information and tutorials on propagation are at //k9la.us/.
Archives of the NOAA/USAF daily 45 day forecast for solar flux and
planetary A index are in downloadable spreadsheet format at
//bit.ly/1IBXtnG and //bit.ly/1KQGbRm .  Sunspot numbers were 11,
23, 27, 47, 38, 39, and 55, with a mean of 34.3.  10.7 cm flux was
93, 92.3, 95, 94.3, 100.4, 101, and 108.5, with a mean of 97.8.
Estimated planetary A indices were 7, 7, 5, 5, 8, 3, and 4, with a
mean of 5.6.  Estimated mid latitude A indices were 8, 5, 5, 6, 9,
4, and 5, with a mean of 6.

‰  END OF 18 WPM transition file ƒ