[SFDXA] ARLP029 Propagation de K7RA

[William Marx]

> SB PROP @ ARL $ARLP029
> ARLP029 Propagation de K7RA
> 
> ZCZC AP29
> QST de W1AW  
> Propagation Forecast Bulletin 29  ARLP029
> From Tad Cook, K7RA
> Seattle, WA  July 21, 2017
> To all radio amateurs 
> 
> SB PROP ARL ARLP029
> ARLP029 Propagation de K7RA
> 
> Average daily sunspot number this week declined just 1.7 to 26.6,
> even though there were two days in the reporting week with no
> sunspots, July 18 and 19.  The blank sun condition continued at
> least one more day on Thursday, July 20 which lands it on the first
> day of the next reporting week, July 20 to 26.
> 
> Average daily solar flux was 85.9, down 1.1 from the previous week.
> 
> Average planetary A index rose 3.9 points to 13, average
> mid-latitude A index rose from 9.6 to 10.9.
> 
> A coronal mass ejection (CME) on July 16 struck at 0545 UTC driving
> the planetary A index to 41, and 27 the following day.
> 
> Predicted solar flux is 70 on July 21 to 27, 75 on July 28, 90 on
> July 29 through August 11, 85 on August 12 and 13, 80 on August 14,
> 74 on August 15 to 19, 75 on August 20 to 24, and 90 on August 25 to
> September 3.
> 
> Predicted planetary A index is 8, 12 and 8 on July 21 to 23, 5 on
> July 24 through August 4, then 25, 10 and 8 on August 5 to 7, 5 on
> August 8 to 14, 8 on August 15 and 16, then 15 and 12 on August 17
> and 18, 5 on August 19 to 31, and 25, 10 and 8 on September 1 to 3.
> 
> F. K. Janda, OK1HH of the Czech Propagation Interest Group sent us
> this geomagnetic activity forecast for the period July 21 to August
> 8, 2017
> 
> "Geomagnetic field will be: 
> Quiet on July 25 and 26, August 1 and 2 
> Mostly quiet on July 24, 27, 30 and 31, August 4, 8 
> Quiet to unsettled July 23, August 3 
> Quiet to active on July 21 and 22, 28 and 29, August 7 
> Active to disturbed on August 5 and 6 
> 
> Amplifications of the solar wind from coronal holes are expected on
> July 21, (23 and 24, 28 and 29), August 6 to 8
> 
> Remark: 
> - Parenthesis means lower probability of activity enhancement and/or
> lower reliability of prediction."
> 
> David Moore sent a link to an excellent NY Times science article
> titled "Unlocking Mysteries in the Sun's 11-Year Cycle."
> 
> http://nyti.ms/2tdddgv
> 
> Another interesting article:
> 
> https://cosmosmagazine.com/space/studying-the-solar-cycle
> 
> And the latest from Tamitha Skov:
> 
> http://bit.ly/2uOPeob
> 
> http://bit.ly/2vqusbs
> 
> 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 July 13 through 19, 2017 were 55, 58, 34, 26,
> 13, 0, and 0, with a mean of 26.6. 10.7 cm flux was 92.3, 93.9,
> 91.6, 86.5, 85.6, 78.2, and 73.1, with a mean of 85.9.  Estimated
> planetary A indices were 4, 4, 4, 41, 27, 7, and 4, with a mean of
> 13. Estimated mid-latitude A indices were 5, 3, 4, 29, 23, 7, and
> 5, with a mean of 10.9.
> NNNN
> /EX