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The K7RA Solar Update


After nine days with no sunspots, sunspot group 2729 emerged on December 5. The sunspot number on that date was 16. Average daily solar flux for the week was 68.9, unchanged from last week. On Thursday, December 6 the appearance of 2729 continued, with a sunspot number of 17 and the sunspot area increasing from 30 to 50 millionths of a solar hemisphere.

Average daily planetary A index rose from 3.3 to 7, while average mid-latitude A index went from 2.1 to 4.9.

Predicted solar flux for the next 45 days is 70 on December 7-8, 69 on December 9, and 68 on December 10 through January 20.

Predicted planetary A index is 10 on December 7, 8 on December 8-9, 5 on December 10-16, 8 on December 17-18, 5 on December 19-27, 8 on December 28, 12 on December 29-30, 10 on December 31, 12 on January 1, 8 on January 2-5, 5 on January 6-12, 8 on January 13-14, and 5 on January 15-20.


Geomagnetic activity forecast for the period December 7, 2018 to January 2, 2019 from F.K. Janda, OK1HH.

Geomagnetic field will be:

Quiet on December 10, 12-15, 19-21, 23

Quiet to unsettled on December 18, 22, 25-27, January 1

Quiet to active on December 9, 11, 16, 24, January 2

Unsettled to active on December 7-8, 17, 30-31

Active to disturbed on December (28-29)

Solar wind will intensify on November 30 and on December 7-9, (10-12, 15-18, 24-27) 28-31, January 1, (2). Parenthesis means lower probability of activity enhancement."


The current Space Weather Highlights ( from NOAA shows updated predictions for smoothed sunspot numbers and solar flux through the end of 2022. As of last month, the predictions ended in 2019.

I’ve been curious to see their prediction for the upcoming solar minimum. If you look on pages 10 and 11 (somewhat obscured by a formatting error) you can see the predicted numbers. The prediction for this month shows a smoothed sunspot number of 10 for December 2018, then declining to 2 in July 2020 through January 2021, then 1 during February 2021 through January 2022, and 0 after that through the end of 2022.

I thought this cycle was supposed to bottom out in 2019 or 2020, but this seems to suggest a disappearance of sunspots in 2022. I wouldn’t bet on it, even though there has been some scary conjecture about a future grand minimum. I am checking some sources and hope to see NOAA clarify this.


Here is an article about observing plasma activity around sunspots to predict space weather:


David Moore sent this article about a view of the solar North Pole:


Mike Schaffer, KA3JAW, observes propagation on the FM broadcast band, and says the winter FM DX season is underway. "On December 2, an FM-DXer near Hamilton, Ontario, Canada reported on the TV/FM Skip Log under the Dxworld website of the reception of five FM stations via Es propagation towards his southwest sector for twenty-one minutes." The list includes stations in Texas, Louisiana and Kansas, from 1551 to 1612 UTC.

For now, at least, you can see the entries here:


Tamitha Skov posted this long video on indices:

Here is her latest video:


This weekend is the ARRL 10-meter Contest. While solar activity is low enough that it doesn’t support 10-meter propagation very well, there is always the winter sporadic-E activity. See for more info.


For more information concerning radio propagation, see the ARRL Technical Information Service at For an explanation of numbers used in this bulletin, see


An archive of past propagation bulletins is at More good information and tutorials on propagation are at


Monthly propagation charts between four USA regions and twelve overseas locations are at


Instructions for starting or ending email distribution of ARRL bulletins are at


Sunspot numbers for November 29 through December 5, 2018 were 0, 0, 0, 0, 0, 0, and 16, with a mean of 2.3. 10.7 cm flux was 67.8, 67.9, 69.4, 69, 68.4, 68.7, and 70.9, with a mean of 68.9. Estimated planetary A indices were 3, 3, 8, 12, 10, 8, and 5, with a mean of 7. Estimated mid-latitude A indices were 2, 2, 4, 9, 9, 5, and 3, with a mean of 4.9.





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