It was a quiet week in space weather (January 11-17) with zero sunspots over the weekend and geomagnetic indicators rising only slightly.

Compared to last week, average daily sunspot numbers declined from 11.9 to 7, but average daily solar flux went from 69.9 to 70.7. Seems counter-intuitive that sunspot and solar flux would move in opposite directions, but these are all very low numbers anyway, and any change is slight. Also, there are no sunspot numbers between zero and 10 due to the arcane and somewhat confusing way they are counted. The number gets 10 points for each sunspot group, and one point for each sunspot in those groups. Therefor the minimum possible sunspot number if there is any sunspot activity is 11.

Geomagnetic indicators were quiet, with average daily planetary A index moving from 5.4 to 6.1, and mid-latitude A index from 4.6 to 4.9.

Predicted solar flux is 71 on January 19-25, 72 on January 26-27, 70 on January 28 to February 17, 72 on February 18-23, and 70 on February 24 to March 4.

Predicted planetary A index is 8, 15, 12, 12, 10 and 8 on January 19-24,  5 on January 25-27, 10 on January 28, 5 on January 29 to February 3, 8 on February 4-5, 5 on February 6-8, then 8, 12 and 10 on February 9-11, 5 on February 12-14, 20 on February 15-16, 18 and 12 on February 17-18, 5 on February 19-23, 10 on February 24, 5 on February 25 to March 2, and 8 on March 3-4.

Geomagnetic activity forecast for the period January 19 to February 14, 2018 from F.K. Janda, OK1HH and the Czech Propagation Interest Group.

“Geomagnetic field will be:
Quiet on January 19, 30-31, February 3, 6-8
Mostly quiet on February 2, 9
Quiet to unsettled on January 23-27, 29, February 1
Quiet to active on January 20-21, 28
Active to disturbed on January 22, February (4-5, 10)

Amplifications of the solar wind from coronal holes are expected
on January 20-23, 28-31, February 5-6, (7, 9,) 10-12

Remark:
- Parenthesis means lower probability of activity enhancement.
- Current forecasts are continuing to be less reliable.”


Interesting article about preserving a long running hand-drawn record of solar images: http://bit.ly/2DmPnUF

For the latest from Tamitha Skov see: https://www.youtube.com/channel/UCkXjdDQ-db0xz8f4PKgKsag



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 11-17, 2018 were 12, 0, 0, 0, 12, 13, and 12, with a mean of 7. 10.7 cm flux was 70.8, 70.9, 70.8, 70.5, 70.2, 71.1, and 70.9, with a mean of 70.7. Estimated planetary A indices were 2, 4, 7, 14, 9, 4, and 3, with a mean of 6.1. Estimated mid-latitude A indices were 2, 3, 7, 11, 7, 3, and 1, with a mean of 4.9.