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SB PROP @ ARL
$ARLP036
ARLP036
Propagation
Forecast
ZCZC AP36
QST de W1AW
Propagation
Forecast
Bulletin 36
ARLP036
From ARRL
Headquarters
Newington, CT
September 4,
2026
To all radio
amateurs
SB PROP ARL
ARLP036
ARLP036 The
ARRL Solar
Report
Forecast of
Solar and
Geomagnetic
Activity,
courtesy of
NOAA Space
Weather
Prediction
Center, 31
August - 26
September
2026.
Solar activity
is expected to
be at very low
to low levels,
with a chance
for moderate
levels and a
slight chance
for high
levels
throughout the
forecast
period.
No proton
events are
expected at
geosynchronous
orbit.
The greater
than 2 MeV
electron flux
at
geosynchronous
orbit is
expected to be
at high levels
on 31 Aug - 06
Sep, then
again from
16-23 Sep.
Levels are
expected to be
at normal to
moderate
levels from 07
- 15 Sep, and
again from
24-26 Sep.
Geomagnetic
field activity
is expected to
decrease from
unsettled
levels on 31
Aug to mostly
quiet levels
from 01-11 Sep
and again from
17-23 Sep.
Unsettled to
active
conditions are
expected from
12-16 Sep due
to negtive
polarity CH
HSS influence,
then again
from 24-26 Sep
under positive
polarity CH
HSS influence.
Weekly
Commentary on
the Sun, the
agnetosphere,
and the
Earth's
Ionosphere,
September 3,
2026
A moderately
strong solar
flare (class
M3.0), which
peaked in the
northeastern
part of the
solar disk on
September 2 at
19:36 UTC, was
accompanied by
a coronal mass
ejection
(CME). This
occurred in
NOAA active
region No.
4524, which
was observed
as NOAA No.
4510 during
the previous
solar
rotation.
Based on its
reappearance
and activity,
we can
conclude that
the expected
decline in
overall solar
activity in
the first half
of September
will not be as
severe as
originally
anticipated.
In the first
half of
September, we
can expect
only a very
gradual
increase in
solar activity
and likely
only a few
geomagnetically
active days.
Above all,
however, we
can expect a
recurring rise
in solar
activity
around the
autumn equinox
which is
precisely the
combination
that typically
leads to a
noticeable
improvement in
ionospheric
propagation of
shortwave
signals.
The subsequent
rise
in geomagnetic
activity
immediately
following the
equinox could,
with a bit of
luck, bring
another brief,
follow-up
improvement at
its onset.
The Predicted
Planetary A
Index for
September 4 to
September 10
is 5, 5, 5, 5,
5, 5, and 5
with a mean of
5.0. The
Predicted
Planetary K
Index is 2, 2,
2, 2, 2, 2,
and 2 with a
mean of 2.0.
10.7
centimeter
flux is 100,
95, 95, 95,
95, 100, and
100 with a
mean of 97.1.
For more
information
concerning
shortwave
radio
propagation,
see www.arrl.org/propagation
and the ARRL
Technical
Information
Service web
page at www.arrl.org/propagation-of-rf-signals.
For an
explanation of
numbers used
in this
bulletin, see
www.arrl.org/the-sun-the-earth-the-ionosphere.
Information
and tutorials
on propagation
can be found
at http://k9la.us.
NNNN
/EX
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