It has been an active period for space weather. At 2240 UTC on November 11, the Australian Space Forecast Center issued a geomagnetic disturbance warning: “Combined CME and coronal hole effects are expected to become geo-effective on 12-Nov, resulting in active to minor storm conditions.” They predicted quiet to minor storm conditions on November 12, and unsettled to active conditions on November 13.
A few days ago the Washington Post ran this story about a possible geomagnetic storm: http://wapo.st/1MSkLZG
The Washington Post also shared this video from NASA of the recent solar flare eruption: http://bit.ly/1NMyi3P
David Moore sent this link last week about a geomagnetic disturbance on November 4 which made planes disappear from air traffic control screens in Sweden: http://phys.org/news/2015-11-sweden-solar-flare-flight.html
The College A index (measured near 64.9 deg N. latitude, near Fairbanks, Alaska) on that date was a very high 55. Stockholm is around 59.3 deg N. latitude. It is generally true that geomagnetic disturbances are more intense at higher latitudes.
Over the past week (November 5-11, our reporting week for data covers Thursday through Wednesday) compared to the previous seven days average daily sunspot number declined from 90.3 to 72.3, and average daily solar flux went from 118.3 to 109.4.
Geomagnetic activity increased, with average daily planetary A index going from 14.7 to 25 and mid-latitude A index from 12 to 19.
The latest forecast from USAF/NOAA has solar flux at 107 on November 13, 113 on November 14-15, 110 and 107 on November 16-17, 105 on November 18-22, 110 on November 23-25, and 115 on November 26-27. Solar flux peaks at 120 on November 28-30 before dropping to a low of 100 on December 14-15. Solar flux is expected to rise to 120 again about ten days later.
Predicted planetary A index is 12, 20 and 12 on November 13-15, then 8 on November 16-17, 5 on November 18-25, 8 on November 26, 5 on November 27, 8 on November 28-29, 25 on November 30 and December 1, then 15, 8, 5, 12, 25, 18 and 12 on December 2-8 and 8 on December 9-13.
Petr Kolman, OK1MGW, of the Czech Propagation Interest Group expects geomagnetic conditions to be quiet to active on November 13-14, mostly quiet November 15-21, quiet on November 22-23, quiet to unsettled November 24-25, mostly quiet November 26-29, active to disturbed November 30 and December 1, quiet to active December 2, quiet to unsettled December 3-4, quiet to active December 5, active to disturbed December 6, quiet to active December 7, and quiet to unsettled December 8-9.
He expects increases in solar wind on November 13-14, November 30 through December 2, and December 5-7.
I have automated searches running constantly for appearances of the word “sunspot” on the web and in news stories, but not all the results refer to actual solar events. For instance, (this was new to me) in Great Britain it seems that sunspot is also a word for any popular winter travel destination at lower latitudes. Another recent search revealed Sunspot is the name of one of the My Little Pony figures, from an on-line collector’s forum. But the strangest was a link to an EDM (electronic dance music) mp3 file titled (I am not making this up), “Powerful X-Class Solar Flare Erupts from Active Sunspot.”
Sometimes I DJ EDM at local dances. Perhaps I should give it a listen.
Included with December 2015 QST is a reproduction of the first QST magazine, which was published 100 years ago in 1915. On page three is a passage related to propagation that applies now, 100 years later:
“December Radio Relay Bulletin
The cool weather has arrived, static is getting better every night, and the owners of relay stations are returning to their instruments.”
Also included is a list of all known Amateur Radio stations in North America. In 1915 they operated CW only using spark gap transmitters, and they made up their own call signs. I was pleased to see of the three amateurs in Washington state, here in Seattle was 7NG (later W7OE), Howard S. Pyle, 3376 York Road, Seattle. I believe he was born in 1896, so he would probably have been 19 years old at the time. Years later he was an author of many popular books and magazine articles on Amateur Radio.
In that first issue is a very serious sounding discussion of how to set up networks to pass messages across the country. In the text they mentioned “Reliability and Certainty” and “Reliability and Celerity. I had never heard of celerity, but it is a real word, meaning rapidity of motion or action and swiftness of movement.
For more information concerning radio propagation, see the ARRL Technical Information Service 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 athttp://arrl.org/w1aw-bulletins-archive-propagation. More good information and tutorials on propagation are at http://k9la.us/.
My own archives of the NOAA/USAF daily 45 day forecast for solar flux and planetary A index are in downloadable spreadsheet format athttp://bit.ly/1VOqf9B and http://bit.ly/1DcpaC5 .
Click on “Download this file” to download the archive, and ignore the security warning about file format. Pop-up blockers may suppress the download.
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 athttp://arrl.org/bulletins.
Sunspot numbers for November 5 through 11 were 75, 86, 79, 70, 67, 65, and 64, with a mean of 72.3. 10.7 cm flux was 109.9, 115.2, 115, 107.7, 107.6, 105.4, and 105, with a mean of 109.4. Estimated planetary A indices were 16, 15, 43, 14, 26, 38, and 23, with a mean of 25. Estimated mid-latitude A indices were 11, 11, 29, 11, 22, 32, and 17, with a mean of 19.