Low solar activity continued over the past reporting week (January 18-24) with zero sunspots visible after January 19. Average daily sunspot number changed from 7 over the previous seven days to 3.3 this week. Average daily solar flux was down slightly from 70.7 to 70. Geomagnetic indicators were also quiet.

Predicted solar flux is 70 on January 26 through February 16, 68 on February 17, 69 on February 18-19, 68 on February 20-26, and 70 on February 27 through March 11.

Predicted planetary A index is 8 on January 26-27, then 5, 8, 10 and 8 on January 28-31, 5 on February 1-3, 8 on February 4-5, 5 on February 6-8, then 8, 12 and 8 on February 9-11, 5 on February 12-14, then 8, 12, 8, 10, 10 and 8 on February 15-20, 5 on February 21-23, 10 on February 24, 5 on February 25 through March 2, 8 on March 3-4, 5 on March 5-7, then 8, 12, 8 and 5 on March 8-11.

The OK1HH Geomagnetic activity forecast for the period January 26 to February 21, 2018.

Geomagnetic field will be:

Quiet on January 31, February 3, 6-8, 13-14

Mostly quiet on February 2, 9, 15, 19

Quiet to unsettled on January 26-27, 30, February 1, 12

Quiet to active on January 28-29, February 4-5, 11, 16-18, 20

Active to disturbed on February 10, 21

Amplifications of the solar wind from coronal holes are expected on January 28-31, February 5-6, (7, 9,) 10-12, 16-18

Remark:

- Parenthesis means lower probability of activity enhancement.

- Current forecasts are continuing to be less reliable.

F. K. Janda, OK1HH

Czech Propagation Interest Group

Compiling this geomagnetic activity weekly forecasts since 1978).

Here is a graph of mode usage during 2017 compiled by ClubLog.org:  http://bit.ly/2DCPw2e

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 18-24, 2018 were 12, 11, 0, 0, 0, 0, and 0, with a mean of 3.3. 10.7 cm flux was 71.1, 70.8, 69.6, 68.3, 70.1, 70.5, and 69.9, with a mean of 70. Estimated planetary A indices were 2, 8, 8, 10, 12, 4, and 9, with a mean of 7.6. Estimated mid-latitude A indices were 1, 6, 5, 8, 8, 3, and 6, with a mean of 5.3.