QST de W1AW  
Propagation Forecast Bulletin 34  ARLP034
>From Tad Cook, K7RA
Seattle, WA  August 25, 2017
To all radio amateurs 

SB PROP ARL ARLP034
ARLP034 Propagation de K7RA

All solar indicators rose over the past week (August 17 to 23), with
average daily sunspot number increasing from 15.3 to 39.9, and
average daily solar flux from 72 to 84.6, compared to the previous
seven days.
 
Predicted solar flux is 79 on August 25, 80 on August 26, 78 on
August 27 to 30, 75 on August 31, 78 on September 1 and 2, 75 on
September 3 to 7, 80 on September 8, 85 on September 9 to 14, 88 on
September 15 and 16, 90 on September 17 to 22, 85 and 80 on
September 23 and 24, 78 on September 25 to 29, 75 on September 30
through October 4, 80 on October 5, and 85 on October 6 to 8.
 
Predicted planetary A index is 8 on August 25, 5 on August 26 and
27, 8 on August 28 and 29, 10 on August 30, 18 on August 31 to
September 1, 14 on September 2, 5 on September 3 to 7, then 10 and 8
on September 8 and 9, then 5 on September 10 to 12, 25 on September
13, 30 on September 14 and 15, then 25, 8, 10 and 6 on September 16
to 19, 5 on September 20 to 25, then 12, 24, 18 and 14 on September
26 to 29, 5 on September 30 through October 4, and 10 and 8 on
October 5 and 6 and 5 October 7 and 8.
 
And now from our correspondents in Eastern Europe:
 
'Solar activity forecast for the period August 25 to August 31, 2017
 
Activity level: mostly low 
X-ray background flux (1.0 to 8.0 A): in the range A8.0 to B4.5 
Radio flux (10.7 cm): a fluctuation in the range 75 to 95 f.u. 
Events: class C (0 to 5/day), class M (0 to 4/period), class X (0/period),
proton (0/period)
Relative sunspot number (Ri): in the range 11 to 80 
 
Martina Exnerova 
RWC Prague, Astronomical Institute, Solar Dept., Ondrejov, Czech
Republic
 
Geomagnetic activity forecast for the period August 24 to August 31, 2017
 
Quiet: Aug 26 to 29 
Unsettled: Aug 24 and 25, 30 and 31 
Active:    Aug possible Aug 31 
Minor storm: 0 
Major storm: 0 
Severe storm: 0 
 
Geomagnetic activity summary: 
Currently, an active episode has been recorded.  At the Budkov
observatory, the local K-index did not exceed level 4.
 
Thursday, August 24, we expect at most unsettled conditions.  Next
day, Friday, August 25, we expect geomagnetic activity decrease to
quiet to unsettled level.

Quiet to unsettled conditions are predicted for the rest of forecast
period.  At the end of August, active episode is possible about
August 31.
 
Tomas Bayer 
RWC Prague 
Institute of Geophysics of the ASCR, Prague 
Department of Geomagnetism 
Budkov observatory (BDV)' 
 
Did you witness the eclipse on Monday?  I found a group of my
neighbors gathered on the street corner after 1700 UTC, and they had
one of those taped-together box arrangements for projecting the
image.  We were in Seattle, north of the band of darkness that
spread over northern Oregon.  Someone drove by with a box of those
special safe eclipse glasses, and they worked very well.
 
Reports from friends who travelled to Madras, in Eastern Oregon's
Jefferson County reported that in the middle of the totality band
they saw the sky go totally dark, and stars illuminated the sky.
 
Scott Craig, WA4TTK of Nashville, Tennessee sent this, along with a
link to eclipse photos he took:
 
'Thought you might like these.  They are photos of Monday's eclipse
taken here in Nashville.  I took them and keep looking at them
because I find them fascinating.'
 
sc-photo-tn.com/?page_id=2389 
 
For more information concerning radio propagation, see the ARRL
Technical Information Service at
arrl.org/propagation-of-rf-signals.  For an explanation of
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/.
 
Monthly propagation charts between four USA regions and twelve
overseas locations are at arrl.org/propagation.
 
Instructions for starting or ending email distribution of ARRL
bulletins are at arrl.org/bulletins.
 
Sunspot numbers for August 17 to 23, 2017 were 30, 41, 33, 44, 43,
48, and 40, with a mean of 39.9. 10.7 cm flux was 76.7, 80, 86.8,
86, 87.1, 90.2, and 85.1, with a mean of 84.6.  Estimated planetary
A indices were 29, 21, 31, 22, 11, 23, and 25, with a mean of 23.1.
Estimated mid-latitude A indices were 20, 20, 23, 21, 13, 16, and
17, with a mean of 18.6.