The K7RA Solar Update

Sunspot group 2733 appeared on Tuesday with a sunspot number of 18, and on Wednesday it increased in size with a sunspot number of 19, which was also the sunspot number on Thursday, January 24. See images of this sunspot group at http://www.solarham.net/regions/2733.htm. This sunspot is a remnant of old Solar Cycle 24. Average daily sunspot numbers increased to 5.3, from zero the previous week. Average daily solar flux increased slightly from 69.4 to 69.8.

The average daily planetary A index increased from 4.9 to 5.9, while mid-latitude A index was unchanged at 4. The predicted solar flux is 72 on January 25-29, 70 on January 30 through February 4, 69 on February 5-16, 71 on February 17-28, 70 on March 1-3, and 69 on March 4-10.

The planetary A index is predicted at 18, 10 and 3 on January 25-27, 5 on January 28-30, 8 on January 31, then 15, 12 and 8 on February 1-3, 5 on February 4-18, then 18, 25, 18 and 10 on February 19-22, 5 on February 23-26, then 10 and 15 on February 27-28, 12 and 8 on March 1-2, and 5 on March 3-10.

Tomas Bayer of the Institute of Geophysics of ASCR, Department of Geomagnetism, Budkov observatory sends this geomagnetic activity forecast for January 25-31, 2019:

Quiet: Jan 27-30

Unsettled: Jan 25-26, 31

Active: Jan 31

Minor storm: 0

Major storm: 0

Severe storm: 0

Geomagnetic activity summary:

After the last active event (January 23, local K-index has reached 4) we expect geomagnetic activity to decrease to quiet to unsettled level. We expect the most unsettled episode about January 25 and 26, and, additionally, at the end of forecast period, January 31. Between these events, January 27-30, we expect quiet conditions.

Next week we will return to geomagnetic forecasts from Frantisek Janda, OK1HH. He is on Facebook at https://www.facebook.com/OK1HH.

Dr. Skov’s latest video, although by now several days old: https://www.youtube.com/watch?v=AlLjlHjffzY

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 17 through 23, 2019 were 0, 0, 0, 0, 0, 18, and 19, with a mean of 5.3. 10.7 cm flux was 68.6, 68.8, 69.7, 69.2, 69.9, 70.7, and 71.5, with a mean of 69.8. Estimated planetary A indices were 7, 6, 4, 4, 4, 3, and 13, with a mean of 5.9. Estimated mid-latitude A indices were 5, 5, 2, 2, 2, 2, and 10, with a mean of 4.

SOURCE ARRL