08/13/2021

The K7RA Solar Update

Tad Cook, K7RA, Seattle, reports: Solar activity continues to be very weak, and
the latest 45-day outlook seems to indicate more of the same ahead. Sunspots
only appeared on 3 out of the 7 days in the August 5 - 11 reporting week, and
these days were not consecutive.

Average daily sunspot numbers actually rose a little, from 6 to 9.9. Average
daily solar flux softened from 74.8 to 73.7. Average daily planetary A index
went from 8 to 6.3, while middle latitude averages were 7, down from 8.7 last
week.

Predicted solar flux over the next few weeks shows a predicted maximum of only
75 on just one day, September 11. The solar flux forecast from USAF and NOAA
shows 73 on August 13-14; 72 on August 15-19; 73 on August 20; 74 on August 21
- September 1; 73, 72, 72, 74, and 74 on September 2-6; 73 on September 7-10;
75 on September 11; 72 on September 12-15; 73 on September 16, and 74 on
September 17 and beyond.

Predicted planetary A index is 8 on August 13-15; 5 on August 16-22; 8 on
August 15-16; 5 on August 17-22; 8, 12, and 8 on August 23-25; 5 on August 26 -
September 1; 8 and 12 on September 2-3; 8 on September 4-6; 5 on September
7-11; 12, 10, and 10 on September 12-14, and 5 on September 15-18.

Strangely, the planetary A index for September 5 is listed as 58, which I was
certain was an error. I wrote to SWPC.Webmaster@noaa.gov[1] and received no
reply as yet.  This outlier value was repeated in Thursday's forecast.
Wednesday's prediction was done by forecasters Stover and Houseal, and
Thursday's was from Trost and Houseal. I have not checked earlier forecasts to
see when this value first showed up. New forecasts[2] appear daily on the SWPC
website.

OK1HH is away for another week, so two of his colleagues - Martina Pavelkova[3]
of RWC Prague, Astronomical Institute, Solar Department, Ondrejov, Czech
Republic, and Tomas Bayer, RWC Prague, Institute of Geophysics of the ASCR,
Prague, Department of Geomagnetism, Budkov Observatory - are sitting in to
present the geomagnetic activity forecast for August 13 - 19.

o Activity level: mostly very low

o X-ray background flux (1.0-8.0 A): in the range A3.5-A7.0

o Radio flux (10.7 centimeters): a fluctuation in the range 70-75

o Events: class C (0-2/period), class M (0/period), class X (0/period),

o proton (0/period)

o Relative sunspot number (Ri): in the range 0-55

Geomagnetic activity forecast for the period August 13-August 19, 2021:

o Quiet: Aug 13-16, 19

o Unsettled: Aug 16-18

o Active: possible Aug 16-17

o Minor storm: 0

o Major storm: 0

o Severe storm: 0

Geomagnetic activity summary: Next week, we expect quiet-to-unsettled
conditions generally. Until Sunday, August 15, we expect the quiet-to-unsettled
level closer to the lower end of the scale.

After Monday, August 16, more unsettled conditions are possible. Between August
16 and August 18, more unsettled conditions are probable. Within this interval,
an isolated active event is also possible.

I spotted an interesting item[4] on Southgate Amateur Radio News.

Sunspot numbers for August 5 - 11 were 36, 0, 0, 11, 0, 0, and 22, with a mean
of 9.9. The 10.7-centimeter flux was 74.3, 74.4, 73.7, 73.5, 73, 73.3, and
73.8, with a mean of 73.7. Estimated planetary A indices were 3, 7, 11, 5, 5,
7, and 6, with a mean of 6.3. Middle latitude A index was 3, 9, 9, 6, 6, 9, and
7, with a mean of 7.

For more information concerning radio propagation, visit[5] the ARRL Technical
Information Service, read[6] "What the Numbers Mean...," and check out this
propagation page[7].

A propagation bulletin archive[8] is available. For customizable propagation
charts, visit the VOACAP Online for Ham Radio[9] website.

Instructions[10] for starting or ending email distribution of ARRL bulletins
are on the ARRL website.

Share[11] your reports and observations.

[1] mailto:SWPC.Webmaster@noaa.gov
[2] ftp://ftp.swpc.noaa.gov/pub/forecasts/45DF/
[3] mailto:sunwatch@asu.cas.cz
[4] https://bit.ly/3sd5LNr
[5] http://arrl.org/propagation-of-rf-signals
[6] http://arrl.org/the-sun-the-earth-the-ionosphere
[7] http://k9la.us/
[8] http://arrl.org/w1aw-bulletins-archive-propagation
[9] https://www.voacap.com/hf/
[10] http://arrl.org/bulletins
[11] mailto:k7ra@arrl.net

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