The K7RA Solar Update 09/01/2017

A new video from Dr. Skov: https://youtu.be/qvjfFpRMQpY


Average daily sunspot numbers and solar flux declined this week (August 24-30). Average daily sunspot number went from 39.9 to 33.3, while average daily solar flux declined to 81.2 from 84.6.

Average planetary A index declined from 23.1 to 7.1, and average mid-latitude A index went from 18.6 to 7.4.

The latest forecast shows planetary A index at 24, 16, 12 and 8 on September 1-4, 5 on September 5-6 then 8, 10 and 8 on September 7-9, 5 on September 10-12, 25 on September 13, 30 on September 14-15, then 25 and 12 on September 16-17, 8 on September 18-19, 5 on September 20-22, 10 on September 23-24, then 8, 15, 25, 18, 15 and 8 on September 25-30, then 5 on October 1-4, 10 and 8 on October 5-6, 5 on October 7-9, 25 on October 10, 30 on October 11-12, then 25, 12 and 8 on October 13-15.

Predicted solar flux is 92 on September 1-2, 91 on September 3, 90 on September 4-7, 80 on September 8, 85 on September 9-14, 88 on September 15-18, 85 on September 19-20, then 82 and 80 on September 21-22, and 78 on September 23-25, 77 and 75 on September 26-27, 74 on September 28-29, 72 on September 30 through October 3, 75 and 80 on October 4-5, 85 on October 6-11 and 88 on October 12-15.


Geomagnetic activity forecast for the period September 1-27, 2017 from OK1HH.

“Geomagnetic field will be:
Quiet on September 10-11, 20-21
Mostly quiet on September 4-6, 23, 26
Quiet to unsettled September 3, 8-9, 19, 22, 27
Quiet to active on September 2, 7, 12, 16-17, 24
Active to disturbed on September 1, 13-15, 18, 25

Remark:
Parenthesis means lower probability of activity enhancement and/or lower reliability of prediction.”


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 August 24-30, 2017 were 43, 39, 35, 22, 17, 35, and 42, with a mean of 33.3. 10.7 cm flux was 78.8, 80.8, 77.5, 78.2, 81.6, 84.3, and 86.9, with a mean of 81.2. Estimated planetary A indices were 11, 5, 5, 10, 4, 10, and 5, with a mean of 7.1. Estimated mid-latitude A indices were 16, 7, 5, 6, 3, 10, and 5, with a mean of 7.4.
http://www.arrl.org/news/the-k7ra-solar-update-490