venerdì 23 novembre 2018

The K7RA Solar Update

We saw sunspots return recently, but only for a week, November 13-19. From last week’s bulletin, average daily sunspot number rose from 3.1 to 9.4, while average daily solar flux rose from 68.5 to 70.8.

That week-long sunspot appearance was sunspot number 2727, but last weekend another smaller sunspot appeared briefly, so brief that it was not assigned a number, but significant because the polarity was reversed, so it is a sunspot from the upcoming Solar Cycle 25. See for details on the brief appearance.

Mike Schaffer, KA3JAW, pointed out that this was the second recent reverse polarity sunspot, after an earlier one on Friday, November 9.

Geomagnetic indicators were quieter, with average planetary A index dropping from 8.1 to 3.3, while average mid-latitude A index declined from 6.3 to 2.1.

Predicted solar flux is 69 on November 23-29, 68 on November 30 through December 2, 69 and 70 on December 3-4, 71 on December 5-15, 72 on December 16-17, 71 on December 18, 68 on December 19-29, 69 on December 30-31, and 71 on January 1-6.

Predicted planetary A index is 5 on November 23-24, 8 on November 25-27, 5 on November 28-30, then 15 and 30 on December 1-2, 10 on December 3-4, 8 on December 5-6, 12 on December 7-8, 8 on December 9, 5 on December 10-15, then 8, 8, 10 and 8 on December 16-19, 5 on December 20-27, 15 and 30 on December 28-29, 10 on December 30-31, 8 on January 1-2, 12 on January 3-4, then 8 and 5 on January 5-6.

Geomagnetic activity forecast for the period November 23 to December 19, 2018 from F.K. Janda, OK1HH.

Geomagnetic field will be:

Quiet on November 23-25, 29-30, December 12-15

Quiet to unsettled on November 26, December 3-4, 10, 16, 18-19

Quiet to active on November 27-28, December 11, 17

Unsettled to active on December (1, 5-9)

Active to disturbed on December 2

Solar wind will intensify on November (23, 30) and on December 1-3, (4-6,) 7-9, (10-12, 17-18).

Parenthesis means lower probability of activity enhancement.

From Tamitha Skov: "After the horrific fires in southern California this month, the Thanksgiving holiday holds a very special meaning. As you might have heard me mention before, several of my friends were recently evacuated due to the Woolsey fire and one even lost their home in Malibu Lake. It’s no exaggeration when I say it will take years for their lives to return to normal. I feel very fortunate that my home was spared.

While my family and I sit down to dinner and count our blessings today, I realize my family has grown a bit larger over this past year. It was just a year ago that I began writing these emails to you on a weekly basis. Slowly but surely, I’ve been sharing bits and pieces of my life with you both here and on Patreon. Many of you have graciously written back and shared bits and pieces of your life with me in return. These ‘gift exchanges,’ as I call them, have enriched my life so much. So much, in fact, that I can't help but think of you as part of my family on a day like today.

So, while the Sun takes a breather and gives us a Thanksgiving reprieve this week, know that you all are in my thoughts. The current forecast may be a little bit on the dull side while we wait for a new chance for a solar storm, but I for one, have all the joy and excitement I need right here.” Here is her latest video:

D. Moore sent this:

This weekend is the CQ World Wide DX CW Contest. See for details.

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 15 through 21, 2018 were 13, 14, 13, 14, 12, 0, and 0, with a mean of 9.4. 10.7 cm flux was 68.4, 71.1, 73.3, 72.3, 71.1, 70.5, and 68.8, with a mean of 70.8. Estimated planetary A indices were 2, 2, 1, 3, 4, 6, and 5, with a mean of 3.3. Estimated mid-latitude A indices were 1, 1, 1, 2, 2, 5, and 3, with a mean of 2.1.