The K7RA Solar Update

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

Radio Blackout hits U.S.:

https://bit.ly/3zNlkno

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

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

https://youtu.be/QDf6eyTCbe4

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.

For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, 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 .

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/ .

Also, check this article:

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 .

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.