SB PROP @ ARL $ARLP036
ARLP036 Propagation de K7RA
ZCZC AP36
QST de W1AW
Propagation Forecast Bulletin 36 ARLP036
From Tad Cook, K7RA
Seattle, WA September 5, 2014
To all radio amateurs
SB PROP ARL ARLP036
ARLP036 Propagation de K7RA
Sunspot activity continued to weaken over the past seven days
(August 28 through September 3). Average daily sunspot numbers
declined from 113.4 to 85.1, and average daily solar flux went from
130.5 to 126.7. Geomagnetic activity was up recently, with average
planetary A index increasing from 7.4 to 14.7, nearly double the
values from the August 21 to 27 period week earlier.
The latest predicted solar flux values are 150 on September 5, 155
on September 6 and 7, 150 on September 8, 145 on September 9 to 11,
130 on September 12, 115 on September 13, 110 on September 14 and
15, 120 on September 16, 130 on September 17 to 19, 135 on September
20 and 21, then 130, 125 and 120 on September 22 to 24, and 115 on
September 25 and 26.
Predicted planetary A index is 8, 10, 20, and 15 on September 4 to
7, 8 on September 8 and 9, 5 on September 10 to 12, 8 on September
13, and 5 on September 14 to 24.
One encouraging sign is the GOES-15 X-Ray Background flux has risen
over the past few days. It was C1.2 on September 2 and C1.0 on
September 3 and 4, and it hasn't had a C reading in quite some time.
This is actually more significant than solar flux regarding effect
on the ionosphere. You can see the background flux daily at
http://www.swpc.noaa.gov/ftpdir/latest/DSD.txt . Checking the
quarterly record, you can see that X-Ray background flux has not
been this high since early July:
http://www.swpc.noaa.gov/ftpdir/indices/quar_DSD.txt
OK1MGW expects geomagnetic conditions will be quiet to active
September 5 and 6, quiet to unsettled September 7 and 8, mostly
quiet September 9, quiet on September 10 to 12, quiet to unsettled
September 13, active to disturbed September 14 and 15, mostly quiet
September 16 and 17, quiet September 18 to 21, quiet to active
September 22, active to disturbed September 23 and 24, quiet to
unsettled September 25 and 26, quiet to active September 27 and 28,
and quiet to unsettled September 29 and 30.
OK1MGW expects an increased solar wind on September 5 to 8, 14 and
15, 22 and 23 and 26 to 29.
An interesting article from the phys.org science news portal about
sunspots is at http://phys.org/news/2014-09-clues-solar.html .
Carl Zelich, AA4MI of Chuluota, Florida reports very poor
conditions. A week ago he reported that for the previous week he
worked Y4/AI5P, 9A6W, EU3DN, S51DX, OK1IF, LY5O, 9K2HN, HK1N, and
HA2NEP. He heard 3D2AC, and commented: "very sparse."
August has passed, so we can now look at our 3-month moving average
of daily sunspot numbers. Average daily sunspot numbers for the
three months ending August 31 was 109.2, the lowest since fall 2013.
This last period was centered on July. For each of the three month
periods in 2014 centered on January through July, the averages were
138.5, 146.4, 148.2, 129.6, 118.4, 112.8, and 109.2.
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 August 28 through September 3 were 78, 73, 64,
90, 94, 105 and 92, with a mean of 85.1. 10.7 cm flux was 118.6,
120.1, 123.1, 124.8, 126.6, 136, and 138, with a mean of 126.7.
Estimated planetary A indices were 21, 21, 15, 15, 11, 10, and 10,
with a mean of 14.7. Estimated mid-latitude A indices were 17, 20,
11, 13, 12, 10, and 11, with a mean of 13.4.
NNNN
/EX
