SB PROP @ ARL $ARLP048
ARLP048 Propagation de K7RA
ZCZC AP48
QST de W1AW
Propagation Forecast Bulletin 48 ARLP048
From Tad Cook, K7RA
Seattle, WA December 2, 2022
To all radio amateurs
SB PROP ARL ARLP048
ARLP048 Propagation de K7RA
No new sunspots appeared over the past reporting week, November 24
to 30. But sunspots were visible every day. Then on December 1
three new sunspot groups emerged. The sunspot number rose from 12
to 49 and the total sunspot area went from 10 to 330.
Sunspot numbers and solar flux declined during this reporting week
(November 24 to 30), with average daily Sunspot number dropping from
66 to 46, and average daily solar flux from 116.5 to 108.3.
Solar wind streams from coronal holes kept geomagnetic indicators
active, with average daily planetary A index jumping from 5.1 to
18.6, and middle latitude A index from 3.4 to 14.
On Wednesday, November 30 the magnetometer at Fairbanks, Alaska
showed the college A index at 54, the highest value over the past
month. No doubt this produced aurora. The next day the disturbance
continued, with collage A index at 51. These are very large
numbers.
The current prediction from Thursday night has solar flux reaching a
peak of 130 this weekend, rather than 135 recently predicted. This
is much earlier than the prediction in yesterday's ARRL Letter. We
might also see solar flux below 100 around December 24.
Look for flux values of 120 and 124 on December 2 and 3, 130 on
December 4 and 5, 125 on December 6 and 7, then 120, 125, 125, 130,
115 and 110 on December 8 to 13, 105 on December 14 to 17, 100 on
December 18 to 23, then 95, 105 and 110 on December 24 to 26, 115 on
December 27 to 30, and 120 on December 31, then 125 on January 1 to
6, 2023.
The planetary A index prediction is 20, 10, 18 and 12 on December 2
to 5, 5 on December 6 and 7, 10 and 8 on December 8 and 9, 5 on
December 10 to 16, 10 on December 17 and 18, 5 on December 19 to 21,
then 20, 15, 12, and 10 on December 22 to 25, then 15, 18, 10, 18
and 10 on December 26 to 30, 5 on December 31 through January 3,
2023, 8 on January 4 and 5, and 5 on January 6 to 12.
OK1HH wrote:
"The course of solar and geomagnetic activity and therefore the
course of shortwave propagation in the last seven days differed
significantly from the week before.
The solar wind speed has increased significantly (from 300 km/s to a
fluctuation between 700 and 800 km/s) and the activity of Earth's
magnetic field mostly increased.
The changes began on 25 November at 0230 UTC when a shock wave in
the solar wind hit the Earth. In the ionosphere we could first
observe an increase in MUF. Further development of the disturbance
continued only by further irregular deterioration of shortwave
propagation.
Enhanced solar flaring activity, including Coronal Mass Ejections
(CMEs), did give rise to predictions of higher geomagnetic activity,
but without the possibility of more precise timing.
On December 1, a new larger sunspot group appeared over the
southeastern limb of the Sun. So solar activity will not drop, but
will probably rise again over the next few days.
Shortwave propagation should therefore no longer deteriorate, rather
the shortest shortwave bands will gradually open up a little better.
In the northern hemisphere of the Earth, however, the opening
intervals will be shorter than in recent weeks."
Research: "Iterative Construction of the Optimal Sunspot-Number
Series"
https://bit.ly/3VLbTtX
This one is spreading fast, all about hams in Montana on PBS:
https://www.montanapbs.org/programs/ham/
Thanks to K7SS and N7SO for the above.
Solar wind news:
https://bit.ly/3EVkeUW
Send your tips, reports, observations, questions and comments to
k7ra@arrl.net .
For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation and the ARRL Technical Information
Service 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/ .
Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .
Sunspot numbers for November 24 through 30, 2022 were 61, 55, 60,
56, 52, 25, and 12, with a mean of 46. 10.7 cm flux was 109.7,
108.5, 107.1, 107.2, 107, 107.9, and 111, with a mean of 108.3.
Estimated planetary A indices were 6, 20, 16, 15, 24, 25, and 24,
with a mean of 18.6. Middle latitude A index was 6, 15, 12, 10, 18,
20, and 17, with a mean of 14.
NNNN
/EX
