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ARRL Propagation Bulletin ARLP005 (2017)

SB PROP @ ARL $ARLP005
ARLP005 Propagation de K7RA

ZCZC AP05
QST de W1AW  
Propagation Forecast Bulletin 5  ARLP005
From Tad Cook, K7RA
Seattle, WA  February 3, 2017
To all radio amateurs 

SB PROP ARL ARLP005
ARLP005 Propagation de K7RA

Over the past reporting week (January 26 through February 1) average
daily sunspot number declined 21.1 points to 31.6, compared to the
previous seven days.

Average daily planetary A index increased from 8 to 15.6, and
average mid-latitude A index rose 5 points to 11.4.

Predicted solar flux is 75 on February 3, 74 on February 4 and 5, 75
on February 6 to 10, 77 on February 11 and 12, then 78, 79 and 81 on
February 13 to 15, 83 on February 16 to 18, 85 on February 19 to 21,
80 on February 22 to 24, then 75 and 76 on February 25 and 26, 75 on
February 27 through March 1, 74 on March 2 and 3, 72 on March 4 and
5, 75 and 76 on March 6 and 7, 77 on March 8 to 11 and 78, 79 and 81
on March 12 to 14.

Predicted planetary A index is 16, 14, 12, 10 and 8 on February 3 to
7, 5 on February 8 to 13, 15 on February 14, 10 on February 15 and
16, 8 on February 17 and 18, 5 on February 19 to 21, 10 and 15 on
February 22 to 23, 10 on February 24 to 26, then 25, 20 and 18 on
February 27 through March 1, 15 on March 2 to 4, then 10 and 8 on
March 5 and 6, 5 on March 7 to 12, 15 on March 13, 10 on March 14
and 15, and 8 on March 16 and 17.

Geomagnetic activity forecast for the period February 3 to March 2,
2017 from OK1HH.  Geomagnetic field will be:

Quiet on February 12, 26
Mostly quiet on February 10 and 11, 13 and 14, 22 and 23
Quiet to unsettled on February 9, 21, 27
Quiet to active on February 4 to 6, 8, 16 and 17, 20, 25, 28
Active to disturbed on February 3, 7, 15, 18 and 19, 24, March 1 and
2

Amplifications of the solar wind from coronal holes are expected on
February 3 to 7, (8 and 9,) 16 to 21, (22,) 26 and 27

Remark:
- Parenthesis means lower probability of activity enhancement.

Thanks to David Moore for this article on how NASA's Fermi Gamma-ray
Space Telescope sees events on the sun's far side:

http://bit.ly/2kZmd4h

For more information concerning radio propagation, see the ARRL
Technical Information Service at
http://arrl.org/propagation-of-rf-signals. For an explanation of
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 January 26 through February 1, 2017 were 31, 33,
28, 24, 35, 42, and 28, with a mean of 31.6. 10.7 cm flux was 83.1,
80.3, 78.5, 76.6, 77, 76, and 76, with a mean of 78.2. Estimated
planetary A indices were 13, 21, 9, 7, 6, 24, and 29, with a mean of
15.6.  Estimated mid-latitude A indices were 11, 17, 7, 5, 5, 16,
and 19, with a mean of 11.4.
NNNN
/EX