ARRL

Secure Site Login

News

The K7RA Solar Update

08/23/2019

Spotless days continue this week, with consecutive days without sunspots now at 16 days, according to spaceweather.com as of August 22.

Average daily solar flux for all practical purposes was unchanged, from 67.4 last week to 67.5 this week. Average daily planetary A index went slightly lower from 6.3 to 4.4.

Predicted solar flux looks the same as it has been for months now, at 67 on August 23 to September 11, 68 on September 12-21 and 67 again on September 22 through October 6.

The forecast for planetary A index stands at 5 on August 23-25, then 12, 12 and 8 on August 26-28, 5 on August 29-31, then with a recurring coronal hole, 38 and 14 on September 1-2, 5 on September 3-5, 8 on September 6-7, then 5 on September 8-15, 7 on September 16-17, 6 on September 18, 5 on September 19-21, 8 on September 22-24, 5 on September 25-27, then with the return of that coronal hole 38 and 14 on September 28-29, 5 on September 30 through October 2, 8 on October 3-4 and 5 on October 5-6.

Geomagnetic activity forecast for the period August 23-September 18, 2019 from F.K. Janda, OK1HH who has issued weekly forecasts since January, 1978.

Geomagnetic field will be:

Quiet on: September 4-5, 9-15
Quiet to unsettled on: August 29-31, September 3, 6-8
Quiet to active on: August (23-25,) September 16-18
Unsettled to active on: August (26-28), September 2
Active to disturbed: September 1

Solar wind will intensify on: August 27-29, (30-31,) September 1-2, (4-7). Parenthesis means lower probability of activity enhancement.

There was an error in last week’s bulletin, in which we misidentified a callsign from Reunion Island when it was really St. Pierre et Miquelon. Because of the proximity to Nova Scotia, I always thought it part of Canada, but it is really a French possession. That’s right, a possession of France right here in North America.

Ken, N4SO reports working XP3A (Greenland) with FT8 on 18.1 MHz, a new one for him.

Interesting course from WX6SWW about indices: https://www.youtube.com/watch?v=zVgZQqUYemc

And her latest forecast: https://youtu.be/GlpdWxXUnAk

Curious about spotless days? http://www.sidc.be/silso/spotless

Note that 1954 had more spotless days than last year, and it was just prior to the biggest solar cycle (Cycle 19) in recorded history.

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 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 15 through 21, 2019 were 0, 0, 0, 0, 0, 0, and 0, with a mean of 0. 10.7 cm flux was 67.6, 67.5, 68, 67.5, 67.7, 67.3, and 66.8, with a mean of 67.5. Estimated planetary A indices were 4, 5, 4, 6, 4, 4, and 4, with a mean of 4.4. Middle latitude A index was 4, 6, 6, 7, 4, 7, and 5, with a mean of 5.6.

 



Back