QST de W1AW  
Propagation Forecast Bulletin 42  ARLP042
>From Tad Cook, K7RA
Seattle, WA  October 15, 2021
To all radio amateurs 

SB PROP ARL ARLP042
ARLP042 Propagation de K7RA

Although we saw sunspots on every day of this reporting week
(October 7-13), solar activity declined somewhat. Average daily
sunspot numbers went from 30.7 to 23.7, and average daily solar flux
from 86.9 to 85.6. Geomagnetic indicators were higher, with average
daily planetary A index rising from 8.1 to 12.4, and average daily
middle latitude A index from 6.7 to 10.1.

On Saturday, October 9, Spaceweather.com reported a strong
Earth-directed M1.6 class solar flare and CME erupting at 0640 UTC,
causing a shortwave radio blackout over the Indian Ocean. This
caused the planetary A index on October 12 to hit 45, and Alaska's
College A index to read 60.

Predicted solar flux is 82 on October 15, 80 and 78 on October
16-17, 76 on October  18-22, 85 on October 23-24, then 90, 100, 95
and 90 on October 25-28, 88 on October 29-30, 85 on October 31
through November 5, 88 on November 6, 85 on November 7-13, 88 on
November 14-15, 90 on November 16, 88 on November 17-18, and back to
100 on November 22.

Predicted planetary A index is 8 on October 15-16, 5 on October 17,
12 on October 18-19, 8 on October 20, 5 on October 21-24, 10 on
October 25, 5 on October 26 to November 1, 8 on November 2, 5 on
November 3-5, 10 on November 6-7, 8 on November 8-9, 5 on November
10-12, then 10, 12, 12, 10 and 8 on November 13-17, and 5 on
November 18-20, then 10 on November 21, and 5 through the end of the
month.

Geomagnetic activity forecast for the period October 15 to November
09, 2021 from F.K. Janda, OK1HH.

'Geomagnetic field will be:
quiet on: October 16-17, November 3, 5,
quiet to unsettled on: October 20-22, 24, 26-27, 30-31, November 4,
quiet to active on: October 23, 25, November 6,
unsettled to active on: October (15, 18-19, 28-29,) November (1-2,) 7-9,
Active to disturbed: Nothing predicted.

'Solar wind will intensify on October (19, 22, 25,) 27-31, November
1, 9.

'Parenthesis means lower probability of activity enhancement.'

On October 12, Spaceweather.com reported in an email alert: 'Last
night, a coronal mass ejection (CME) struck Earth's magnetic field,
sparking a moderately strong geomagnetic storm. Auroras were sighted
in the USA as far south as Nebraska with lights so bright in some
places that onlookers successfully photographed them using cell
phones.'

The November 2021 issue of QST arrived, and the article on page 70,
'Propagation Tools and Resources for Contesting' by WO1N, KC2G and
members of the Yankee Clipper Contest Club, shares some great
resources, not only of interest to contest operators.

Here's an interesting article on 60 meters propagation:

https://bit.ly/2YNlHLN

The latest video report from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/XrPW4337IHI

If you would like to make a comment or have a tip for our readers,
please email the author at, [email protected] .

For more information concerning shortwave radio propagation, see
www.arrl.org/propagation and the ARRL Technical Information
Service web page at, at arrl.org/propagation-of-rf-signals.
For an explanation of numbers used in this bulletin, see
arrl.org/the-sun-the-earth-the-ionosphere.

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/.

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

Sunspot numbers for October 7 through 13, 2021 were 13, 13, 14, 38,
35, 26, and 27, with a mean of 23.7. 10.7 cm flux was 85.7, 92.4,
81, 84.5, 88.5, 83.5, and 83.5, with a mean of 85.6. Estimated
planetary A indices were 5, 4, 5, 9, 13, 45, and 6, with a mean of
12.4. Middle latitude A index was 3, 3, 4, 9, 15, 32, and 5, with a
mean of 10.1.