SB PROP @ ARL $ARLP038
ARLP038 Propagation de K7RA

ZCZC AP38
QST de W1AW
Propagation Forecast Bulletin 38 ARLP038

From Tad Cook, K7RA

Seattle, WA September 22, 2023
To all radio amateurs

SB PROP ARL ARLP038
ARLP038 Propagation de K7RA

ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0249UTC on 22
SEPTEMBER 2023 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE:

"Solar wind streams from a pair of coronal holes are expected to
mildly increase geomagnetic activity at times during the interval
late 22-Sep to 24-Sep.

"INCREASED GEOMAGNETIC ACTIVITY EXPECTED FROM 22-24 SEPTEMBER 2023."

Nine new sunspot groups appeared this week, but the averages were
lower.

A new sunspot group appeared every day from September 15-17, four
more on September 18, and one each day on September 19-20.

On Thursday, the start of the next reporting week two more sunspot
groups appeared.

Average daily sunspot numbers declined from 138.1 to 118.4, while
average daily solar flux went from 159.9 to 149.3.

The Autumnal Equinox in the Northern Hemisphere occurs on Saturday,
September 23 at 2:50 AM EDT, or 0650z. The change in seasons has
been evident recently with improving propagation on 10 and 12
meters.

A fast moving CME hit Earth on September 18, sparking dramatic
displays of aurora across the northern tier of North America and in
Europe as far south as France.

Alaska's college A index was 49 and 61 on September 18-19, while the
planetary A index was 30 and 49.

Predicted solar flux is 162, 162 and 165 on September 22-24, 160 on
September 25-28, 135 on September 29-30, then 130, 135, 130 and 135
on October 1-4, 140 on October 5-6, 135 on October 7-8, then 140,
145 and 145 on October 9-11, then 150, 150, 155 and 150 on October
12-15, and 155, 150, 145 and 145 on October 16-19, then 150, 150 and
145 on October 20-22, 140 on October 23-24, 135 on October 25-27,
then 130, 135, 130 and 135 on October 28-31.

Predicted planetary A index is 15 on September 22, 22 on September
23-24, then 12 and 8 on September 25-26, 5 on September 27-28, 12
and 8 on September 29-30, 5 October 1-11, 8 on October 12, then 5 on
October 13-19, 12 on October 20, 5 on October 21-24, then 8, 12 and
8 on October 25-27, then 5 on October 28 into the first week of
November.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - September 21, 2023 from OK1HH:

"Although the site https://solarham.net/ launched on March 15, 2006,
created and still maintained solely by Kevin,VE3EN, is primarily
intended for amateur radio users, it is also very well regarded by
professional astronomers. In addition to information about the Sun,
it contains everything needed to understand the causes of changes in
the ionosphere, and also provides an overview and forecast of the
Earth's magnetic field activity. On Thursday, September 21, we read:
'Solar activity is predicted to remain at low (C-Flares) to moderate
(M-Flares) levels during the next 24 hours. AR-3435 is considered
the most likely region to produce a moderate to strong solar flare.'

"The information can be supplemented by saying that the level of
solar activity has been rising in recent days, and this rise was
accompanied by an increase in solar wind speed from 400 km/s to over
600 km/s between 18-20 September. In particular, the solar wind
proton influx increased significantly on 18 September; moreover, a
geomagnetic disturbance with intensity G2 (Moderate) to G3 (Strong)
took place on 18-19 September.

"The Earth's ionosphere responded to these events with a significant
decrease in MUF, especially since 18 September. Shortwave conditions
were above average for the last time on 10-12 September, including a
positive phase of the disturbance on the latter day. Around the
equinox we usually expect improvement, but now it was the opposite
as a result of disturbances.

"As another very good source of information, I can particularly
recommend the Space Weather Monitor (https://www.ionosonde.iap-kborn.de/actuellz.htm), as it also
contains the most important data on the Earth's ionosphere."

From reader David Moore, on Parker Solar Probe:

https://bit.ly/3ELWC5E

More Parker Solar Probe news:

https://bit.ly/3EOVEpl

A new video from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/pU6i_2FVR2g

Send your tips, reports, observations, questions, and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us
which mode you were operating.

Also, check this article from September, 2002 QST:

https://bit.ly/3Rc8Njt

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/ .

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for September 14 through 20, 2023 were 110, 96, 88,
94, 139, 143, and 159, with a mean of 118.4. 10.7 cm flux was
145.2, 139.1, 140.4, 144.6, 154.5, 166.1, and 155.5, with a mean of
149.3. Estimated planetary A indices were 18, 7, 7, 16, 30, 49, and
16, with a mean of 20.4. Middle latitude A index was 13, 7, 5, 14,
21, 38, and 15, with a mean of 18.1.
NNNN
/EX


--- MBSE BBS v1.0.8.4 (Linux-x86_64)
* Origin: American Radio Relay League (3:633/280.2@fidonet)

SB PROP @ ARL $ARLP038
ARLP038 Propagation de K7RA

ZCZC AP38
QST de W1AW
Propagation Forecast Bulletin 38 ARLP038

From Tad Cook, K7RA

Seattle, WA October 4, 2024
To all radio amateurs

SB PROP ARL ARLP038
ARLP038 Propagation de K7RA

ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 0042UT/04 OCTOBER
2024 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE.

Two coronal mass ejections first observed on 01-Oct and 03-Oct are
expected to impact Earth over 04-05 Oct. Lack of analyzable corona
graph imagery makes arrival time predictions uncertain.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION
FROM 04-06 OCTOBER 2024.

GEOMAGNETIC ACTIVITY FORECAST:
04 Oct: G3, chance of G4
05 Oct: G3, chance of G4
06 Oct: G1-G2

New sunspot groups emerged on every day over the past week. Two new
regions appeared on September 26, another on September 27, two more
on September 28, another on September 29, another on September 30,
three more on October 1 and another on October 2, for a total of
eleven.

Average daily sunspot number rose from 137.1 to 164.7, and average
daily solar flux from 164.3 to 213.1. Average daily planetary A
index shifted from 14.3 to 9.6.

Predicted solar flux is 310 on October 4-6, 300 on October 7, 290 on
October 8-10, 175 on October 11-16, 170 on October 17-21, then 175,
180, 185, 190 and 195 on October 22-26, then 200 on October 27-29,
205 on October 30 through November 4, then 200 and 185 on November
5-6 and 175 on November 7-12.

Predicted planetary A index is 54, 94, 72, 22 and 15 on October 4-8,
5 on October 9-10, then 20 and 19 on October 11-12, then 5 on
October 13-21, then 28 and 10 on October 22-23, 5 on October 24-26,
and 10 on October 27, then 5 on October 28-31, 10 on November 1-2, 5
on November 3-5, then 10, 20, and 19 on November 6-8, and 5 on
November 9 and the foreseeable future.

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - October 3, 2024 from OK1HH:

"After AR3811 disappeared from our field of view behind the
southwestern limb of the solar disk on September 12, it was
continuously tracked by helioseismological methods until September
29, when it reappeared in the southeast, numbered AR3842. Its size
and activity on the far side of the Sun suggested that we could look
forward to a lot of activity in October.

"And so, it did. When solar flare X7.1/2b was observed on October 1
with a maximum at 2220 UT, the second largest in the current 11-year
cycle, I planned to start with this announcement. But when flare
X9.05, newly the largest in X-ray intensity in the same AR3842, was
observed on October 3 at 1218 UT, that was no longer the case.

"The source region of AR3842 was heading straight towards us. So,
the plasma cloud was probably heading directly for our ionosphere.
Unlike the aforementioned X7.1/2b (which thus moved to the third
largest), it is very likely that the CME of October 3 will hit
Earth. We therefore expect a disrupted end of the week.

"This weekend we can expect low MUF and high LUF on shortwave and
QSOs over aurora on VHF. Early next week will see a gradual return
to average and then above average radio wave propagation conditions
in the ionosphere."

From "The New Zealand Herald," Aurora in Auckland:

https://bit.ly/3NcNOde [ https://bit.ly/3NcNOde ]

Radio Blackout hits U.S.:

https://bit.ly/3zNlkno [ https://bit.ly/3zNlkno ]

https://www.space.com/sun-monster-solar-flare-x7-video [ https://www.space.com/sun-monster-solar-flare-x7-video ]


Here is the latest update from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/QDf6eyTCbe4 [ https://youtu.be/QDf6eyTCbe4 ]

Send your tips, reports, observations, questions and comments to
k7ra@arrl.net [ mailto:k7ra@arrl.net ] . When reporting observations, don't forget to tell us

which mode you were operating.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation [ http://www.arrl.org/propagation ] and the ARRL Technical Information

Service web page at, http://arrl.org/propagation-of-rf-signals [ http://arrl.org/propagation-of-rf-signals ] . For

an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere [ http://arrl.org/the-sun-the-earth-the-ionosphere ] .


An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation [ http://arrl.org/w1aw-bulletins-archive-propagation ] . More good

information and tutorials on propagation are at http://k9la.us [
http://k9la.us ] .


Also, check this article:

https://bit.ly/3Rc8Njt [ https://bit.ly/3Rc8Njt ]

"Understanding Solar Indices" from September 2002 QST.

Instructions for starting or ending email subscriptions to ARRL
bulletins are at http://arrl.org/bulletins [ http://arrl.org/bulletins ] .

Sunspot numbers for September 26 through October 2 2024 were 189,
122, 148, 154, 150, 196, and 194, with a mean of 164.7. 10.7 cm flux
was 181.1, 186, 194.5, 197.2, 214.2, 244.6, and 274.4, with a mean
of 213.1. Estimated planetary A indices were 13, 7, 7, 16, 11, 6,
and 7, with a mean of 9.6. Middle latitude A Index was 11, 5, 5, 17,
5, 9, and 6, with a mean of 8.3.
NNNN
/EX

ARRL® The National Association for Amateur Radio®
Unsubscribe [ https://www.arrl.org/opt-in-out ]


--- MBSE BBS v1.0.8.4 (Linux-x86_64)
* Origin: American Radio Relay League (3:633/280.2@fidonet)