Last week’s bulletin featured zero sunspots for the entire seven days. This week (January 12-18) the average daily sunspot number rose to 22.6.

Average daily solar flux rose from 72.5 to 77.1. Average planetary A index declined from 14.3 to 6.

Predicted solar flux is 80 on January 20-23, then 78, 77 and 75 on January 24-26, 77 on January 27 through February 1, 76 on February 2, 75 on February 3-8, 76 on February 9, 77 on February 10—14, 78 on February 15, 80 on February 16-21, 78 on January 22, and 77 on January 23-28.

Predicted planetary A index is 15, 12, 10 and 8 on January 20-23, 5 on January 24-26, then 12, 15, 7, 10, 12 on January 27-31, then 16, 18, 20, 16, 12, 10 and 8 on February 1-7, and 5 on February 8-12, then 8, 22 and 18 on February 13-15, 16 on February 16-18, then 12 and 8 on February 19-20, then 5 on February 21-22 and 12, 15, 7 and 10 on February 23-26.

Geomagnetic activity forecast for the period January 20-February 15, 2017 from F.K. Janda, OK1HH:

Geomagnetic field will be:

Quiet on January 25-26, February 10, 13-14

Mostly quiet on January 24, 30, February 6, 9, 11-12

Quiet to unsettled on January 23, 27, 31, February 1, 3

Quiet to active on January 20-22, 28-29, February 7-8

Active to disturbed on January February 2, 4-5, 15

Amplifications of the solar wind from coronal holes are expected on January 20-21, (22-25,) 26, (31,) February (1-5,) 9, (15)

Remark:

- Parenthesis means lower probability of activity enhancement.

- Observed indicia of upcoming MAJOR CHANGES in solar activity!

  Therefore, the current forecast is less reliable.

Time now to examine the average daily sunspot number for 2016, which was 36.8. Starting from solar cycle 24 minimum in 2008, annual average daily sunspot numbers were 4.7, 5.1, 25.5, 80.1, 82.3, 97.1, 121.2, 70.1 and 36.8.

The January 11, 2017 issue of ARRL Contest Update (current and back issues available at http://www.arrl.org/contest-update-issues) mentions a new online propagation prediction program from G4FKH via RSGB. The link to ITURHFprop is at http://bit.ly/2jTVHFQ.

The Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile is providing new detailed images of the sun. See http://bit.ly/2ka6JKh for details.

More info from regular contributor David Moore: https://www.sciencedaily.com/releases/2017/01/170117101835.htm

John Kelley, K4WY, wrote on January 17: "Great timely info as always thank you! I wanted to share with you that on January 2 on 17 meters I worked E51DMC, VK2DX and ZL4FF all within a spread of an hour. I was in Virginia and running 100 watts to a loop and was really surprised when I checked the SN count and A and K indexes. Could not have been much worse! So, I am at a loss as to how to explain the propagation! But I liked it at least for that hour."

The sunspot number was zero on that date, and the day prior. There was one brief sunspot appearance the next day, then none at all from January 4-11. But given those numbers and daily solar flux (around 72-73) there should be some pretty good propagation during that period. W6ELprop predicts for that date that ZL4FF might receive your 17 meter, 100-watt signal from 1530-1930z fairly reliably.

To VK2DX, the prediction shows good propagation 1800-2100z. To E51DMC, it looks good on 17 meters from 1700-2030z.

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 January 12 through 18, 2017 were 11, 24, 25, 23, 24, 26, and 25, with a mean of 22.6. 10.7 cm flux was 75.5, 74.9, 76.6, 77.5, 78.3, 78.6, and 78.6, with a mean of 77.1. Estimated planetary A indices were 5, 4, 4, 5, 3, 4, and 17, with a mean of 6. Estimated mid-latitude A indices were 3, 3, 3, 2, 2, 3, and 11, with a mean of 3.9.