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ARRL Propagation Bulletin ARLP041 (2016)

SB PROP @ ARL $ARLP041
ARLP041 Propagation de K7RA

ZCZC AP41
QST de W1AW  
Propagation Forecast Bulletin 41  ARLP041
From Tad Cook, K7RA
Seattle, WA  October 7, 2016
To all radio amateurs 

SB PROP ARL ARLP041
ARLP041 Propagation de K7RA

Over the past week (September 29 through October 5), relative to the
previous seven days the average daily sunspot number declined 9
points to 20.7, and average daily solar flux increased from 81.4 to
86.7. Average daily planetary A index increased from 19.7 to 21.4,
and average mid-latitude A index (measured in Virginia) increased
from 12.3 to 15.1.

Hey, think that was bad? At University of Alaska's magnetometer
which supplies us with the College A Index (see
http://bit.ly/2dNZSEu), the number went to 73 on September 29, with
the average of the week at 35.9.

Predicted solar flux from the October 6, 2016 forecast shows 102 on
October 7-8, 105 on October 9, 102 on October 10-12, 100 on October
13, 90 on October 14, 95 on October 15-18, 90 on October 19-21, 85
on October 22-26, 80 On October 27-31, 85 on November 1-2, 90 on
November 3-10, 95 on November 11-14 and 90 on November 15-17.

Predicted planetary A index is 5 on October 7-12, then 8, 5, 8, 10,
20 and 8 on October 13-18, 5 on October 19-22, 20 on October 23, 35
on October 24-26, then 20, 15, 15, 12, 15 and 10 on October 27
through November 1, 5 on November 2-10, then 10, 20 and 8 on
November 11-14, and 5 on November 15-18.

OK1MGW sent this:

"Geomagnetic activity forecast for the period October 7-November 2, 2016

"Geomagnetic field will be:
Quiet on October 7-8, 13-14, 19-20
Mostly quiet on October 9-10, 12,19, November 1-2
Quiet to unsettled on October 11, 15-16, 21
Quiet to active on October 17-18, 22-23, 28-31
Active to disturbed on October 24-27

"Amplifications of the solar wind from coronal holes are expected on
October 16-18, 22-30."

On October 6, NASA released an updated prediction for 10.7 cm solar
flux for the remainder of Cycle 24:

http://solarscience.msfc.nasa.gov/images/f107_predict.jpg

Accompanying text is at
http://solarscience.msfc.nasa.gov/predict.shtml

The average sunspot number for July, August and September was 40.

The 3-month moving averages of daily sunspot numbers for this year,
for periods ending in February through September were 53.5, 49,
45.3, 43.1, 35.4, 33, 33.5 and 40.

If you would like to make a comment or have a tip for our readers,
email the author at k7ra@arrl.net.

For more information concerning radio propagation, see the ARRL
Technical Information Service web page at,
http://arrl.org/propagation-of-rf-signals. For an explanation of the
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/.

Monthly propagation charts between four USA regions and twelve
overseas locations are at http://arrl.org/propagation.

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

Sunspot numbers for September 29 through October 5 were 17, 12, 0,
13, 32, 33, and 38, with a mean of 20.7. 10.7 cm flux was 82.7,
80.6, 81, 82.3, 87.8, 93.1, and 99.3, with a mean of 86.7. Estimated
planetary A indices were 39, 21, 19, 18, 14, 26, and 13, with a mean
of 21.4. Estimated mid-latitude A indices were 22, 15, 14, 15, 12,
18, and 10, with a mean of 15.1.
NNNN
/EX