QST de W1AW  
Propagation Forecast Bulletin 45  ARLP045
>From Tad Cook, K7RA
Seattle, WA  November 13, 2023
To all radio amateurs 

SB PROP ARL ARLP045
ARLP045 Propagation de K7RA

'ASWFC GEOMAGNETIC DISTURBANCE WARNING ISSUED AT 2310 UTC/09
NOVEMBER 2023 BY THE AUSTRALIAN SPACE WEATHER FORECASTING CENTRE:

'G1-G2 geomagnetic conditions are expected over 11-12 Nov, with a
slight chance of G3 due to the anticipated arrival of a halo CME
first observed 09-Nov. Conditions are expected to ease to background
levels on 13-Nov.'

A great, big geomagnetic storm on Sunday disrupted the second day of
ARRL CW Sweepstakes. Planetary A index for the day was 57, and the
highest 3-hour planetary K index readings were 6, 6, 7 and 6.33 from
1200-2100 UTC. This was triggered by a coronal mass ejection (CME).

This reporting week, ending November 8, saw six new emerging sunspot
groups, one on each day, except November 6.

Solar activity improved, with average daily sunspot number
increasing from 76.7 to 89.7. Average daily solar flux rose from
137.5 to 151.7.

Geomagnetic activity increased. Average daily planetary A index
changed from 15.9 to 22.3 and middle latitude A index rose from 11.9
to 14.6.

The most active days were Sunday and Monday when the planetary A
index was 57 and 40, respectively.

Predicted solar flux is 140 on November 10-11, then 145, 130 and 135
on November 12-14, 130 on November 15-16, 123 and 120 on November
17-18, 125 on November 19-22, 130 on November 23-26, then 132, 134
and 134 on November 27-29, 136 on November 30 through December 2,
then 140 and 138 on December 3-4, 136 on December 5-6, then 138, 136
and 134 on December 7-9, 130 on December 10-12, then 125, 123 and
120 on December 13-15, and 125 on December 16-19.

Predicted planetary A index is 10, 8, 8, 12 and 10 on November
10-14, then 5 on November 15-21, then 15, 10 and 15 on November
22-24, then 15, 20, 15 and 8 on November 25-28, then 5 on November
29 through December 5, then 12 and 8 on December 6-7, 5 on December
8-10, then 8, 10, and 8 on December 11-13, and 5 on December 14-18.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - November 9, 2023, from F.K. Janda, OK1HH.

'In agreement with the prediction, two CMEs probably hit the Earth
on 4 and 5 November in succession (at least the second one on 3
November, also in the northern hemisphere of the Sun, was a 'full
halo CME').

'A G1 class geomagnetic storm was expected for the arrival of both
CMEs. The expectation was gradually changed to G2, but in fact its
intensity reached G3 (since 5 November 1743 UT, by K = 7).

'A relatively recently described and still somewhat mysterious
phenomenon, referred to as 'STEVE' (Strong Thermal Emission Velocity
Enhancement), was also observed.

'It looks like an aurora, but unlike the aurora, it can be detected
already in weaker storms (by K = 4 or more). They are caused by hot
(3000 deg C) jets of gas flowing through the Earth's magnetosphere
at speeds in excess of 6 km/s.

'For the shortwave propagation, the positive phase of the
disturbance development (with increase of MUF and overall
improvement) was observed not only on November 4, but even better
after a pause on November 5. This was followed by a massive
deterioration, especially on 6 November, continuing to some extent
on 7 November. Although the influx of fast solar wind with enhanced
proton content continued, an increase in MUF followed with relative
improvement in shortwave propagation conditions as early as 8-9
November.'

On Friday, November 3, W0IY wrote:

'I was very pleased with great conditions to Europe and North Africa
Saturday October 28 at 1700 UTC on 10 meters SSB. Happily working
stations when I saw a spot for Vanuatu. Tuned to the freq and easily
worked him. Didn't change the beam.

'Sunday morning same conditions and there is a spot for Reunion
Island. 1 call.

'Neither sounded like long path. Both strong signals in Cedar
Rapids, Iowa.

'Just seems like odd propagation.'

I ran some paths with W6ELprop software, and to Reunion from W0IY
the best time for 10 meters on this 10,000 mile path would be
1630-1800 UTC, with possible openings also from 1530-1900 UTC.

An article on recent aurora:

https://bit.ly/467cs6d

A solar eruption resembling a 'Canyon of Fire':

https://bit.ly/3sBIGZo

Scientists discover new truth about the Sun's structure:

https://www.indy100.com/science-tech/the-sun-structure-new-discovery

A new video from Dr. Tamitha Skov, WX6SWW.

https://youtu.be/nPrxI0KJmv4

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.

An archive of past propagation bulletins is at
arrl.org/w1aw-bulletins-archive-propagation . More good
information and tutorials on propagation are at k9la.us/ .

Also, check this article from September, 2002 QST:

https://bit.ly/3Rc8Njt

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

Sunspot numbers for November 2 through 8, 2023 were 113, 106, 95,
81, 67, 74, and 92, with a mean of 89.7. 10.7 cm flux was 158.4,
156.1, 155.3, 154.8, 146.2, 145.1, and 145.7, with a mean of 151.7.
Estimated planetary A indices were 7, 4, 14, 57, 40, 18, and 16,
with a mean of 22.3. Middle latitude A index was 4, 3, 12, 30, 27,
11, and 15, with a mean of 14.6.