[SFDXA] K7RA SOLAR update

[Bill]

The K7RA Solar Update
03/12/2021

Tad Cook, K7RA, Seattle, reports: Although solar activity remains low, 
in recent days, as a sunspot rotates to the west off the visible solar 
disc a new one emerges in the east. Sunspot group 2807 recently moved 
over the sun’s western horizon, but on March 9 new sunspot group 2808 
moved across the eastern horizon, and a newer group (2809) has now 
emerged just south of the center of the solar disc. This brought the 
daily sunspot number higher from 11 on Wednesday to 23 on Thursday, 
March 11.

Recent sunspot activity and solar flux still seem soft when compared to 
activity toward the end of 2020, however.

In Bulletins ARLP048, 49, and 50 in 2020 — covering November 19 – 
December 9 — average sunspot numbers were 27.9, 57.6, and 28.9, while 
average daily solar flux was 90.1, 108.1, and 91.9. For the past 3 
weeks, the overall average daily sunspot numbers was 19 (2 weeks prior 
had no sunspots), and average daily solar flux was 77.1.

We can’t do anything but wait and watch, although we /can/ look forward 
to the vernal equinox on Saturday, March 20. Like the autumnal equinox, 
this is always a positive influence on HF propagation, when the northern 
and southern hemispheres are bathed in approximately equal amounts of 
solar radiation. You can count on it.

The average daily sunspot number this week hardly changed, from 18.9 
last week to 18.4. Average daily solar flux shifted marginally higher 
from 76.7 to 78.9.

Solar wind has slackened, so average daily planetary A index went from 
14.7 to 7.6, and the middle latitude numbers changed from 10.4 to 6.1.

Predicted solar flux for the next 30 days is 78 on March 12 – 19; 75, 
76, 78, and 81 on March 20 – 23; 80 on March 24 – 25; 78 and 76 on March 
26 – 27; 75 on March 28 – April 1; 78 on April 2 – 3, and 70, 74, 76, 
72, 71, 72 and 70 on April 4 – 10. After April 18, solar flux may rise 
again above 80, then back to 75 by April 24.

Predicted planetary A index is 12, 20, and 10 on March 12 – 14; 5 on 
March 15 – 17; 12 on March 18 – 19; 20, 18, 12, and 8 on March 20 – 23; 
5 on March 24 – 27; 25, 20, 20, and 10 on March 28 – 31; 5, 15, and 8 on 
April 1 – 3; 5 on April 4 – 7, and 18, 12, 5, and 15 on April 8 – 11. A 
recurring coronal hole may rotate into a geo – effective position on 
April 15 – 16 and another around April 24 – 25, raising the planetary A 
index again to around 20 – 25.

Here’s the geomagnetic activity forecast for March 12 – April 6 from F.K 
Janda, OK1HH.

The geomagnetic field will be:

  * quiet on March 17, (26 – 27,) April 1, 6
  * quiet to unsettled on March 12 – 13, 16, 25, April 3 – 5
  * quiet to active on March 21 – 24, 31
  * unsettled to active March 14 – 15, 18, 29 April 2
  * active to disturbed March 19 – 20, 28, 30
  * Solar wind will intensify on March (12 – 14, 18 – 19,) 20 – 23,
    (27,) 28 – 31, April (1 – 2)

Parenthesis means lower probability of activity enhancement. 
Predictability of changes remains very low, as there are ambiguous 
indications.

Dennis, K7BV, reported: “March 7, while checking the bands for DX, I 
went to 15 meters on FT8 about 1650. The strongest signal by a huge 
margin was S79KW (LI75rj Seychelles) at +27 dB! After a quick contact, I 
moved to a clear frequency to call CQ.  Almost immediately 4S6RSP, –8 dB 
strong. called. A few minutes later VU2AMW at –1 dB called. I also 
noticed YC5YZ calling CQ. Nothing else heard from the region, but S79KW 
remained strong well after this brief 15-meter opening to Southern and 
Southeast Asia.”

Unfortunately the averages at the end of this bulletin sometimes change 
from the preview that appears in Thursday’s edition of */The ARRL Letter 
<http://www.arrl.org/arrlletter>/*. This is my fault and happens from 
time to time. Thanks so much to Don Wright, AA2F, who catches these 
every time, and makes sure the correct averages appear in Friday’s bulletin.

*Aurora seaso*n 
<https://www.steamboatpilot.com/news/celestial-news-aurora-season-returns/> has 
returned in Colorado.

David Moore sent *this 
<https://www.sciencedaily.com/releases/2021/03/210309100127.htm>* from 
/Science News/: “The aurora’s very high altitude booster.”

Sunspot numbers for March 4 – 10 were 32, 14, 23, 14, 12, 23, and 11, 
with a mean of 18.4. The 10.7-centimeter flux was 81.4, 73.2, 77, 77.5, 
79.9, 83.7, and 79.4, with a mean of 78.9. Estimated planetary A indices 
were 11, 5, 16, 10, 6, 3, and 2, with a mean of 7.6. Middle latitude A 
index was 11, 5, 11, 7, 5, 2, and 2, with a mean of 6.1.

For more information concerning radio propagation, *visit 
<http://arrl.org/propagation-of-rf-signals>* the ARRL Technical 
Information Service, *read 
<http://arrl.org/the-sun-the-earth-the-ionosphere>* “What the Numbers 
Mean…,” and *check out <http://k9la.us/>* K9LA’s Propagation Page.

A propagation bulletin *archive 
<http://arrl.org/w1aw-bulletins-archive-propagation>* is available. For 
customizable propagation charts, visit the *VOACAP Online for Ham Radio 
<https://www.voacap.com/hf/>*website.

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