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ARRL Propagation Bulletin ARLP049 (2018)

ARLP049 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 49  ARLP049
From Tad Cook, K7RA
Seattle, WA  December 7, 2018
To all radio amateurs 

ARLP049 Propagation de K7RA

After nine days with no sunspots, sunspot group 2729 emerged on
December 5.  The sunspot number on that date was 16.  Average daily
solar flux for the week was 68.9, unchanged from last week.  On
Thursday, December 6 the appearance of 2729 continued, with a
sunspot number of 17 and the sunspot area increasing from 30 to 50
millionths of a solar hemisphere.

Average daily planetary A index rose from 3.3 to 7, while average
mid-latitude A index went from 2.1 to 4.9.

Predicted solar flux for the next 45 days is 70 on December 7 and 8,
69 on December 9, and 68 on December 10 through January 20.

Predicted planetary A index is 10 on December 7, 8 on December 8 and
9, 5 on December 10 to 16, 8 on December 17 and 18, 5 on December 19
to 27, 8 on December 28, 12 on December 29 and 30, 10 on December
31, 12 on January 1, 8 on January 2 to 5, 5 on January 6 to 12, 8 on
January 13 and 14, and 5 on January 15 to 20.

Geomagnetic activity forecast for the period December 7, 2018 to
January 2, 2019 from F. K. Janda, OK1HH.

"Geomagnetic field will be: 
Quiet on December 10, 12 to 15, 19 to 21, 23 
Quiet to unsettled on December 18, 22, 25 to 27, January 1
Quiet to active on December 9, 11, 16, 24, January 2 
Unsettled to active on December 7 and 8, 17, 30 and 31 
Active to disturbed on December (28 and 29)

Solar wind will intensify on November 30 and on December 7 to 9, (10
to 12, 15 to 18, 24 to 27) 28 to 31, January 1, (2).

Parenthesis means lower probability of activity enhancement."

The current Space Weather Highlights
from NOAA shows updated predictions for smoothed sunspot numbers and
solar flux through the end of 2022.  As of last month, the
predictions ended in 2019.

I've been curious to see their prediction for the upcoming solar
minimum.  If you look on pages 10 and 11 (somewhat obscured by a
formatting error) you can see the predicted numbers.  The prediction
for this month shows a smoothed sunspot number of 10 for December
2018, then declining to 2 in July 2020 through January 2021, then 1
during February 2021 through January 2022, and 0 after that through
the end of 2022.

I thought this cycle was supposed to bottom out in 2019 or 2020, but
this seems to suggest a disappearance of sunspots in 2022.  I
wouldn't bet on it, even though there has been some scary conjecture
about a future grand minimum.  I am checking some sources, and hope
to see NOAA clarify this.

Here is an article about observing plasma activity around sunspots
to predict space weather:

David Moore sent this article about a view of the solar North Pole:

Mike Schaffer, KA3JAW observes propagation on the FM broadcast band,
and says the winter FM DX season is underway.

"On December 2, an FM-DXer near Hamilton, Ontario, Canada reported
on the Tv/Fm Skip Log under the Dxworld website of the reception of
five FM stations via Es propagation towards his southwest sector for
twenty-one minutes."

The list includes stations in Texas, Louisiana and Kansas, from 1551
to 1612 UTC.

For now at least, you can see the entries here:

Tamitha Skov posted this long video on indices:

Here is her latest video:

This weekend is the ARRL 10 meter Contest.  While solar activity is
low enough that it doesn't support 10 meter propagation very well,
there is always the winter sporadic-E activity.  See for more info.

For more information concerning radio propagation, see 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

Monthly propagation charts between four USA regions and twelve
overseas locations are at

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

Sunspot numbers for November 29 through December 5, 2018 were 0, 0,
0, 0, 0, 0, and 16, with a mean of 2.3.  10.7 cm flux was 67.8,
67.9, 69.4, 69, 68.4, 68.7, and 70.9, with a mean of 68.9.
Estimated planetary A indices were 3, 3, 8, 12, 10, 8, and 5, with a
mean of 7.  Estimated mid-latitude A indices were 2, 2, 4, 9, 9, 5,
and 3, with a mean of 4.9.


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