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ARRL Propagation Bulletin ARLP052 (2022)

ARLP052 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 52  ARLP052
From Tad Cook, K7RA
Seattle, WA  December 30, 2022
To all radio amateurs 

ARLP052 Propagation de K7RA

This reporting week (December 22-28) saw declining solar numbers and
rising geomagnetic indicators. Average daily sunspot numbers dropped
from 124.1 to 96.1, and solar flux from 153.8 to 143.8. Average
planetary A index rose from 6.7 to 17.3, and middle latitude numbers
from 5.1 to 12.6.

Predicted solar flux is 164 and 162 on December 30-31, 160  January
1-3, 2023, 158 on January 4, 156 on January 5-6, 140 on January 7-8,
136 on January 9, 130 on January 10-14, then 128 and 125 on January
15-16, 120 on January 17-20, then 125, 135, 136, 138, 132, 134 and
132 on January 21-27, 130 on January 28-29, 135 on January 30, and
140 on January 31 through February 4.

Predicted planetary A index is 16, 14, 10 and 8 on December 30, 2022
through January 2, 2023, 5 and 14 on January 3-4, then 18, 18 and 10
on January 5-7, 5 on January 8-16, then 8, 12, 25 and 20 on January
17-20, 10 on January 21-22, then 20, 15, 10, 15 and 12 on January
23-27, and 10, 5 and 18 on January 28-30, then then 10, 10, 8 and 10
on January 31 through February 3, and a nice quiet 5 beyond that,
perhaps until mid-February.

The observatory at Penticton, British Columbia is the source for our
solar flux numbers, and the staff leaves annually from Christmas to
New Years. The system is automated, and we get the daily noon
readings from this source:

Unfortunately, the system crashed on December 24 and no readings
were posted after Christmas Eve.

Thanks to Dr. Andrew Gray, Research Council Officer at the Dominion
Radio Astrophysical Observatory for monitoring his email while on
holiday and supplying us with the four days of missing data.

From Thomas Bayer, RWC Prague at the Budkov Observatory:

"Geomagnetic activity forecast for the period December 30 - January
05, 2023.

"Quiet: Dec 30, Jan 2-3
Unsettled: Dec 30-31, Jan 3-5
Active: Dec 31-Jan 1, Jan 3-5
Minor storm: Jan 3-4
Major storm: 0
Severe storm: 0

"We expect a transitional geomagnetic activity decrease during the
coming two days. Then, about New Year, we expect partial geomagnetic
activity enhancement again with a possible active event.

"The other active/minor storm event is expected about January 3 - 4
in connection with coronal hole 60/-3.

"Between these events, we expect quiet to unsettled conditions

From F.K. Janda, OK1HH:

"Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere December 30 - January 05, 2023.

"A week ago it seemed that the relatively low solar activity would
remain so until Christmas. All observable sunspot groups had
relatively stable magnetic fields, not enough to generate major

At the same time, a series of geomagnetically disturbed days
continued until 27 December, with highly variable and
difficult-to-predict evolution of ionospheric shortwave propagation.
Average days were irregularly interspersed with above-average ones.

"From December 25, sunspot group AR3169 suddenly began to increase.
Trailing behind it is AR3171, and both are now approaching the
western edge of the solar disk.

"The CME observed on Christmas Eve after a magnetic filament
explosion, likely partially impacted Earth and contributed to the
slow decline in solar wind speed during the third decade (ten day
period) of December.

"According to NOAA forecasts, there is a possibility of G1 class
geomagnetic storms on December 30-31, when the Earth's magnetic
field is likely to hit the Co-rotating Interaction Region (CIR). We
expect increased geomagnetic activity and auroras at higher
latitudes again.

"Thanks to helioseismology, we know of three active regions on the
far side of the Sun. They are large enough to last until their
heliographic longitudes reach the eastern limb of the solar disk.
Therefore, total solar activity should not drop much anytime soon."

Another over-the-top article describing flares as existential

Unusual solar events:

Big 2022 solar news:

A New Year's forecast from Dr. Tamitha Skov, WX6SWW, our Space
Weather Woman:

Don't forget, New Year's Eve (in North America) and New Year's Day
is Straight Key Night:

Send your tips, reports, observations, questions, and comments to

For more information concerning shortwave radio propagation, see and the ARRL Technical Information
Service at . For an
explanation of numbers used in this bulletin, see .

An archive of past propagation bulletins is at . More good
information and tutorials on propagation are at .

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

Sunspot numbers for December 22 through 28, 2022 were 108, 100, 85,
107, 96, 89, and 88, with a mean of 96.1. 10.7 cm flux was 131.3,
127.7, 133.3, 144, 150.5, 159, and 160.4, with a mean of 143.8.
Estimated planetary A indices were 12, 24, 23, 10, 22, 25, and 5,
with a mean of 17.3. Middle latitude A index was 7, 19, 15, 8, 19,
16, and 4, with a mean of 12.6.


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