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ARRL Propagation Bulletin ARLP047 (2023)

ARLP047 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 47  ARLP047
From Tad Cook, K7RA
Seattle, WA  November 27, 2023
To all radio amateurs 

ARLP047 Propagation de K7RA

Geomagnetic conditions were very quiet last weekend, good conditions
for the ARRL Phone Sweepstakes. But there was much more geomagnetic
activity toward the end of the reporting week, when the planetary A
index jumped to 30 and Alaska's College A index reached 60, a very
high value.

This past weekend was the CW portion of the CQ World Wide DX

Solar activity really picked up in the past few days, with three new
sunspot groups on November 17, 18 and 19, then six new groups on
November 20, another on November 21, and three more groups on
Thanksgiving Day, November 23.

Sunspot numbers on Tuesday through Thursday, November 21-23 were
138, 174 and 176, and the total sunspot area on Thursday was 1560
millionths of the solar surface, the largest in a long time.

Average daily sunspot number rose from 80.1 to 83.3, while average
daily solar flux went from 133.8 to 146. Average daily planetary A
index went from 10.4 to 10.1, and middle latitude numbers from 8.6
to 7.3.

Predicted solar flux is 195 on November 24-28, then 190, 185, 155
and 152 on November 29 through December 2, then 150, 148 and 145 on
December 3-5, 140 on December 6-8, 145 on December 9-10, 140 on
December 11-17, 145 on December 18-23, 148 on December 24, 152 on
December 25-26, 155 on December 27-28, then 152, 150 and 148 on
December 29-31.

Predicted planetary A index is 5 and 10 on November 24-25, 15 on
November 26-27, 8 on November 28, 5 on November 29 through December
3, then 10, 16, 12 and 10 on December 4-7, 5 on December 8-11, then
10 and 8 on December 12-13, 5 on December 14-17, then 10, 15 and 12
on December 18-20, then 8, 8, 5, 8 and 8 on December 21-25, and 5 on
December 26-30.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere November 24-30, 2023, from F.K. Janda, OK1HH:

"After passing through a twenty-seven day low in mid-November, solar
activity began to increase. Slowly at first, then steeply in recent
days. What was common to the whole period was that the predictions
of further developments were not fulfilled. Shortwave propagation
conditions were, with a few exceptions, worse than expected.

"In the second half of last week, the Earth's magnetic field was
calm despite the eruption of a magnetic filament on the Sun on
November 16, which threw a CME almost directly toward the Earth. We
expected the CME to arrive on November 19. On the contrary, quiet
days followed on November 19-20. Then, despite seven new sunspot
groups and calm in the Earth's magnetosphere, propagation conditions
did not improve until November 20.

"Improvement occurred on 21 November, when the onset of the
geomagnetic disturbance was accompanied by two positive phases of
development with increases in MUF and an overall improvement in
conditions (at intervals of 10-13 UTC and 16-19 UTC).

"The following evolution could be expected - there was a
deterioration of propagation conditions in the negative phase of the
disturbance development on 22 November. However, the deterioration
was short-lived, after which, thanks to the increasing solar
activity, an improvement occurred already on 23 November.

"Although solar activity continues to increase, there is a coronal
hole near the five active regions in the northeast quadrant of the
solar disk. This configuration will cause further increases in solar
wind speed and therefore more frequent alternation of better and
worse days."

In a message titled "6 Meter F2 November 22" Jon Jones, N0JK wrote:

"Despite a predicted CME impact over the weekend of November 18-19
missing the Earth, the geomagnetic field had minor storm conditions
November 22. The K index went to 5. This was enough of a nudge for
the F2 MUF to climb above 50 MHz to South America.

"I had several HC stations in around 1503z including HC2AO, HC2FG
and HC1MD/2. The opening lasted about 45 minutes then faded. Later
F2 appeared to the Caribbean area. I logged PJ4MM in FK52 at 1615z.

"Stations in the Minneapolis, MN area had an opening to Namibia with
V51WW working numerous W9 and W0 stations on 6 Meter FT8."
In the current issue of the ARRL Letter there is an article about
two hams who are 100 miles apart in Florida who made contact via a
10 meter FM repeater in Switzerland.

The annual ARRL 160-Meter Contest will be this weekend, December

Looking forward, the annual ARRL 10-Meter Contest will be on
December 9-10:

Two new video reports from Dr. Tamitha Skov, WX6SWW:

Two articles on a big sunspot group:
Send your tips, reports, observations, questions and comments to When reporting observations, don't forget to
tell us which mode you were operating.

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

Also, check this article from September, 2002 QST:

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

Sunspot numbers for November 16 through 22, 2023 were 28, 26, 39,
51, 127, 138, and 174, with a mean of 83.3. 10.7 cm flux was 117.9,
119.6, 127.1, 140.1, 156.5, 171.5, and 189.5, with a mean of 146.
Estimated planetary A indices were 8, 3, 3, 4, 5, 18, and 30, with a
mean of 10.1. Middle latitude A index was 7, 3, 2, 3, 4, 15, and 17,
with a mean of 7.3.


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