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SB PROP @ ARL
$ARLP028
ARLP028
Propagation de
K7RA
ZCZC
AP28
QST
de W1AW
Propagation
Forecast
Bulletin 28
ARLP028
From
Tad Cook, K7RA
Seattle,
WA July 26,
2024
To
all radio
amateurs
SB
PROP ARL
ARLP028
ARLP028
Propagation de
K7RA
Solar
activity was a
bit lower this
week. Seven
new sunspot
groups
appeared. The
only day with
no new sunspot
groups was
Sunday, July
21. The next
day two new
sunspot groups
arose, and all
other days
each had one
new group.
Average
daily sunspot
number was
208.1, down
from 215.9,
while average
daily solar
flux declined
from 226 to
193.
Geomagnetic
numbers
remained
quiet, with
average
planetary A
index
unchanged at
6, and middle
latitude
numbers
changing from
8 to 7.3.
Future
geomagnetic
indicators
look very
quiet, for
many weeks.
The
outlook for
the next few
weeks has
solar flux
reaching a
short term
maximum of 230
on August
12-14.
Spaceweather.com
sent out this
alert on July
25.
"MAJOR
FARSIDE SOLAR
FLARE:
Europe's Solar
Orbiter (SolO)
spacecraft
just detected
the most
intense solar
flare of the
current solar
cycle. The
X14-category
explosion
sprayed
energetic
particles
throughout the
solar system,
causing high
dose rates on
Mars and even
hitting Earth
on the
opposite side
of the sun.
The source of
the flare
could turn to
face our
planet late
next week."
Predicted
solar flux is
170 on July
26-27, 165 on
July 28-29,
170 on July 30
through August
1, 165 on
August 2, then
170, 180 and
190 on August
3-5, 200 on
August 6-11,
230 on August
12-14, 210 on
August 15,
then 200 on
August 16-18,
195 and 185 on
August 19-20,
180 on August
21-23, 175 on
August 24, 170
on August
25-27, 165 on
August 28-29,
and 170 on
August 30-31.
Flux values
may climb to
230 again on
September 8-9.
Predicted
planetary A
index is 10,
18 and 8 on
July 26-28, 5
on July 29
through August
14, 8 on
August 15-16,
and 5 on
August 17
through
possibly mid
September, a
long stretch
of very quiet
conditions.
Weekly
Commentary on
the Sun, the
Magnetosphere,
and the
Earth's
Ionosphere for
July 25, 2024.
So here we are
on Thursday,
July 25th.
Initially it
appeared there
would be a
continued
period of high
solar
activity,
including
flares. A
logical
continuing
chain of
predictions of
increased
geomagnetic
activity,
especially
after major
flares. Then
finally at
1351 UTC a
message came
from NOAA
containing the
words:
"WARNING:
Geomagnetic
Sudden Impulse
expected. IP
Shock Passage
Observed: 2024
Jul 25 1315
UTC." The
development
continued and
we could read
the message
from Boulder,
Co.: "SUMMARY:
Geomagnetic
Sudden Impulse
Observed: 2024
Jul 25 1422
UTC.
Deviation: 8
nT. Station:
BOU." After
all, after a
series of
solar flares,
this was no
longer a major
surprise while
the week-old
forecast by
Tom Bayer (RWC
Prague,
Department of
Geomagnetism,
Budkov
Observatory
was fulfilled.
But
it was not a
big surprise,
the previous
major
disturbance
occurred on 28
June, or 26
days ago. If
the mentioned
geomagnetic
disturbance
develops and
lasts longer,
it will
adversely
affect
shortwave
conditions in
the following
days, possibly
until Sunday.
However, the
recovery could
be even faster
due to the
high solar
activity. F.
K. Janda,
A.R.S. OK1HH"
The
latest from
Dr. Tamitha
Skov, Space
Weather Woman,
WX6SWW:
https://youtu.be/BgT8Y2cJjVw
Eruptions: https://bit.ly/4c2BNBb
Havoc: https://bit.ly/4dgMRf3
Reconstructed
sunspot
series:
https://www.eurekalert.org/multimedia/1035992
Storm
forecast:
https://bit.ly/46mWBSL
https://bit.ly/4fjVPd5
Cycle
26: https://bit.ly/3ydtq7Y
Send
your tips,
reports,
observations,
questions and
comments to [email protected].
When reporting
observations,
don't forget
to tell us
which mode you
were
operating.
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.
An archive of
past
propagation
bulletins is
at
www.arrl.org/w1aw-bulletins-archive-propagation.
More
good
information
and tutorials
on propagation
are at http://k9la.us
Also,
check this: https://bit.ly/3Rc8Njt
Instructions
for starting
or ending
email
distribution
of ARRL
bulletins are
at www.arrl.org/bulletins.
Sunspot
numbers for
July 18
through 24
2024 were 276,
269, 212, 200,
173, 167, and
160, with a
mean of 208.1.
10.7 cm flux
was 208.7,
201.6, 207.4,
197.9, 185,
175.5, and
174.8, with a
mean of 193.
Estimated
planetary A
indices were
5, 5, 7, 5, 9,
5, and 6, with
a mean of 6.
Middle
latitude A
Index was 4,
5, 8, 9, 9, 8,
and 8, with a
mean of 7.3.
NNNN
/EX
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