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The K7RA Solar Update 10/29/2021

Tad Cook, K7RA, Seattle, reports: Sunspot activity was up this week, with the average daily sunspot number increasing by nearly five-fold from 11.3 to 54.9. Average daily solar flux rose from 78.6 to 95.7. Currently our sun is peppered with spots.

A new sunspot group appeared on October 22, another on October 24, two more on October 25, and another on October 26. The sunspot number peaked on Thursday, October 28, at 96, and daily solar flux peaked on the same day at 111.7.

Geomagnetic indicators were nice and quiet, but don’t expect that to last. Average daily planetary A index went from 8.4 to 4.4 and average daily middle latitude A index declined from 5.4 to 3.6.

Predicted solar flux looks quite promising, at 113 on October 29; 114 on October 30 – November 1; 110 and 105 on November 2 – 3; 100 on November 4 – 5; 86 on November 6 – 7; 85 on November 8 – 9; 83 on November 10; 82 on November 11 – 15; 85 on November 16 – 20; 94 on November 21; 95 on November 22 – 23; 96 on November 24; 95 on November 25 – 29; 92, 90, and, 88 on November 30 – December 2, and 86 on December 3 – 4.

Predicted planetary A index is 5 on October 29; 40, 35, and 12 on October 30 – November 1; 5 on November 2 – 5; 12, 10, and 8 on November 6 – 8; 5 on November 9 – 14; 10 and 8 on November 15 – 16; 5 on November 17 – 22; 8 on November 23 – 24; 10 on November 25 – 26; 5 on November 27 – 28; 8 on November 29; 5 on November 30 – December 2, and 12, 10, and 8 on December 3 – 5.

On Thursday, reported that a “strong G3-class geomagnetic storm is possible on October 30, when the CME from yesterday’s X-flare is expected to hit Earth’s magnetic field.” This is why the predicted planetary A index on October 30-31 is 40 and 35.

At 0129 UTC on October 29, the Australian Space Forecast Centre issued this geomagnetic disturbance warning: “[Sunspot] AR2887 produced X1.0 flare on October 28 at 1535 UTC, which triggered a halo CME. The CME is expected to arrive at Earth in the first half of UTC day 30 October. As a result, the geomagnetic conditions are expected to reach major storm levels with a chance of severe storm periods. The global Kp index may reach 7 (G-3 level storms). On the local night of 30 October (and maybe 31 October), aurora may be visible from Tasmania and the southern mainland coastal areas. INCREASED GEOMAGNETIC ACTIVITY EXPECTED DUE TO CORONAL MASS EJECTION 30 – 31 OCTOBER 2021.”

This weekend is the CQ World Wide SSB DX Contest, which should be affected by the increased geomagnetic activity. The CW weekend is November 27 – 28. ARRL November CW Sweepstakes is next weekend, November 6 – 8.

Here’s the geomagnetic activity forecast for October 29 – November 23 from F.K. Janda, OK1HH. The geomagnetic field will be:

  • quiet on November 4 – 5, 18 – 19

  • quiet to unsettled on October 31, November 9, 12 – 13, 17, 20, 22

  • quiet to active on October 29, November 1 – 3, 10 – 11, 21, 23

  • unsettled to active on October 30, November 6 – 8, 14, 16

  • Active to disturbed November (15)

  • Solar wind will intensify on October 30 – 31, November 1, (8,)

9 – 10, (11,) 16 – 17

Remarks: Parentheses mean lower probability of activity enhancement.

Darrell, AA7FV, sent this along. He also sent plots of 17-meter WSPR reports for October 28, which, he noted, show the obvious effect of a CME from 1520 to 1550 UTC.

You really should check out his pages on and, which give fascinating details of his activities, and background in astrophysics.

Don’t miss the latest video from Tamitha Skov, WX6SWW.

Mike May, WB8VLC, in Salem, Oregon, reported his contacts on the high HF bands until October 27. He listed only the “interesting QSOs” as there were just too many others from 17 to 10 meters to include. One was an AM contact on 15 on October 24 at 1640 UTC with CT1EHI in Portugal. Signals were solid both ways, he reported.

Another was D4F [Cape Verde] on 10-meter SSB, “the first real strong African-region signal heard in a long time here on 10 meters.”

Others he reported included the HD8R DXpedition in the Galapagos, which he worked on 17 meters at 0129 UTC on October 27. He also worked HD8R on 10, 12, and 15 meters on October 26; E51JD in the South Cook Islands on October 24 on 10 meters (SSB), and VE8WD/m the same day on 15 meters (SSB). “A nice QSO with a ham in Yellowknife running 100 W mobile. He was over S-9 for 2 hours after our contact.”

Here is a Canadian view on solar risks to the power grid, and more on this week’s space weather.

In a message with the subject line, “Good propagation these days,” Angel Santana, WP3GW, reported from Puerto Rico on October 26:

“Yesterday at about 1730 UTC, heard M5JON on 28.505 MHz, which was a surprise since it has been a long time since I heard an English station on 10 meters.” He reported an S-7 report. “Today contacted HD8R on 24.950 MHz split (up 5) up at 1851 UTC. I suppose and hope that the CQ WW SSB this weekend is why I am hearing much activity on all bands.”

Here’s part of a message from Frank Donovan, W3LPL:

“Propagation crossing low and mid latitudes is likely to be normal until likely CME arrival early to mid-day Saturday, then mostly below normal at least until mid-day Sunday.

“We are in the geomagnetically active autumn equinox season through late October with about twice as many geomagnetically active days compared to December, January, June, and July caused by the interplanetary magnetic field (IMF) more frequently persisting in a southward orientation (–Bz).

“Geomagnetic disturbances caused by coronal hole high speed stream effects are likely to remain mostly brief, minor and somewhat less frequent through at least late 2021. The southward oriented (–Bz) component of the interplanetary magnetic field (IMF) plays a crucial but unpredictable role in triggering all geomagnetic storms.

“Brief minor to moderate geomagnetic storms may be gradually triggered when the IMF persists in a southward orientation (–Bz) with enhanced IMF field strength for several hours coincident with the effects of an Earth directed coronal hole high speed stream.

“More frequent, longer duration, minor to severe geomagnetic storms may be triggered suddenly and unpredictably when the IMF persists in a southward orientation (–Bz) with enhanced IMF field strength for several hours or more coincident with the effects of an Earth directed fast CME.

“Mid-latitude northern hemisphere sunset is 56 minutes earlier and day length is 90 minutes shorter than it was on September 22. Daytime ionization and residual nighttime ionization in the far northern polar region is rapidly declining due to steadily increasing polar night effects.”

Sunspot numbers for October 21 – 27 were 11, 28, 32, 46, 81, 95, and 91, with a mean of 54.9. The 10.7-centimeter flux was 81.9, 86.9, 86.8, 93.2, 100.6, 109.3, and 110.9, with a mean of 95.7. Estimated planetary A indices were 7, 4, 3, 4, 5, 5, and 3, with a mean of 4.4. Middle latitude A index was 9, 3, 2, 2, 4, 3, and 2, with a mean of 3.6.

For more information concerning radio propagation, visit the ARRL Technical Information Service, read “What the Numbers Mean…,” and check this propagation page by Carl Luetzelschwab, K9LA.

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

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

Share your reports and observations.


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