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ARRL Propagation Bulletin ARLP019 (2021)

ARLP019 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 19  ARLP019
From Tad Cook, K7RA
Seattle, WA  May 7, 2021
To all radio amateurs 

ARLP019 Propagation de K7RA

Our Sun seems to have fallen back into a very quiet phase, far
different from the way it looked in November 2020. That was six
months ago, and we assumed since we were emerging from a solar
minimum that by now we would be seeing much more solar activity. It
hasn't happened.

More recently, sunspots disappeared after May 1, and solar flux
naturally declined as well.

Sunspots were visible only the first three days of the current
reporting week (April 29 to May 5), so average daily sunspot number
declined from 47.6 last week to 11.9 in the current period.

But early this morning (Friday) a new sunspot group 2822 is emerging
over the Sun's northeastern horizon. You can see it as that white
splotchy mass crossing the upper left on .

Over the past week the average daily solar flux slipped seven points
from 79.2 to 72.2. It seems odd, but both the average daily
planetary and middle latitude A index remained the same for both
weeks, 10.7 and 9.9 respectively.

Predicted solar flux for the next month appears listless, never even
reaching 80, with values of 71 on May 7, 72 on May 8-9, 74 on May
10-11, 75 on May 12-13, 77 on May 14, 79 on May 15-17, 77 on May
18-21, 75 on May 22-24, 74 on May 25-26, 72 on May 27, 70 on May
28-31, 72 on June 1-4 and 74 on June 5-7.

The planetary A index projection shows 5 on May 7-8, 8 on May 9-10,
5 on May 11-13, 15 on May 14-16, 12 on May 17, 5 on May 18-19, then
15 and 10 on May 20-21, 5 on May 22-29, 12 on May 30-31 10 on June
1, and 5 on June 2-6.

Geomagnetic activity forecast for the period May 7 to June 1, 2021
from F.K. Janda, OK1HH.

"Geomagnetic field will be:
quiet on: May 7-8, 18-19, 25-26
quiet to unsettled on: May 9-11, 17, 24, 31, June 1  
quiet to active on: May 12, (20-23, 27)
unsettled to active: May 16, 28-30
active to disturbed: May 13-14, (15)
"Solar wind will intensify on: May (10-11, 16,) 17-18, (21-25,) 28-30.
- Parenthesis means lower probability of activity enhancement.
- Contradictory indications significantly reduce the accuracy of the

In a message at the end of April, W3LPL noted:

"There are usually about twice as many geomagnetic storms during
March and April compared to June and July. The ratio of severe (Kp=8
or 9) storms is much greater.  But the end of geomagnetic storm
season doesn't mean the end of geomagnetic storms, two of the most
severe (Kp=8+) geomagnetic storms during Solar Cycle 24 occurred on
June 22 and 23, 2015.

"We probably won't notice significantly fewer storms until June.
Storms during June and July aren't as frequent or as strong as they
are during the geomagnetic storm seasons (March/April, and
September/October). But geomagnetic storms -- even the most severe
storms (Kp 8 or 9) -- can occur at any time with little warning.

"Earth directed coronal mass ejections (CMEs) are just beginning to
cause occasional geomagnetic storms now that Solar Cycle 25 is more
active. During the next few years CMEs will become the dominant
cause of moderate to severe geomagnetic storms.

"Geomagnetic storms caused by CMEs usually develop more quickly, are
more long lasting and more severe than the mostly minor storms
caused by coronal hole high speed streams during the approximately
four years near solar minimum.

"We've had two moderate (Kp=6) storms so far this year, both during
March. We also had eight minor (Kp=5) storms: five in March and one
each in January, February and April."

Thank you, Frank.

Often I will check for FT8
signals reported on 6 or 10 meters over the most recent 15 minutes.
If I set it to "country of the callsign" instead of my grid square,
I often notice signals detected in the southeast of North America
when nothing is happening here on the west coast.

Right now late at night it is reporting 6 meter FT8 signals over a
545 mile path from N2GHR to N8NQ at 0639 UTC, and then on 10 meters
at 0658 UTC 381 mi KO4FSZ to KC2DUX at -2 dB. That is almost

KB1XP in Connecticut (FN31po) reports, "It seems that 20M early
morning propagation is improving with the increased sunspot activity
lately. I had a brief but productive 20M band opening on 05/03/21
from 05:36 to 05:58 EDT and worked JH1XPA, JA7LGE, JR7RHO Japan
stations on FT8 with good signal reports.  Hopefully this is a sign
of good things to come."

On May 5, WB8VLC reported from Salem, Oregon:

"True to form 10 meters still provides interesting DX. This weekend
like clockwork E51JD was back in on SSB but this opening was short
and much weaker than previous days. But still even with low SFI
numbers he was workable.
"On the 29.6 FM side a good sporadic-E opening on May 2nd brought
the Los Angeles area in with regulars AA6DD, K6YYL and N6OS worked
with typical 59+ reports on 29.6 FM. Then today TI2JS on 29.6 FM.
"The interesting day however was May 3rd when I dropped down to
28.074 FT8 just to see if the band was open, calling CQ DX on FT8. I
use it here at times on a quiet band just to see where I should
point my beam.
"Well this was a mistake, as it brought almost 2 dozen Japan
contacts on 10 FT8 but one station, JD1BMH in Ogasawara Island stood
out of the group and after I signed with Ogasawara on FT8 I dropped
down to 28.072 CW and after just 1 CQ DX JD1BMH Ogasawara saw me on
his waterfall and came down to CW for a quick contact.
"Sigs with Ogasawara were over 559 on CW both directions and after
we signed JD1BMH called CQ for the next 35 minutes.
"No other Japan stations took the bait to move off of FT8 and drop
to CW so it was only Ogasawara worked on CW which was fine for me.
"Today was another interesting day on 29.6 FM with TI2JS in Costa
Rica worked on FM with nobody else heard all day.
"I worked 22 Japan stations on 28.074 FT8, one KL7 and one VK4, all
worked on May 3 on FT8, 28.074.
"On 6 meters on May 2nd, 3rd, and the 4th a bit of 50.125 SSB,
50.094 CW and even some 52.525 FM brought some nice QSOs with
Arizona, Utah and California on 6 meters."

Steve Sacco, NN4X sent these articles about timelines of space
weather storms:

A report from Dr. Tamitha Skov, WX6SWW, from a few days ago:

If you would like to make a comment or have a tip for our readers,
please email the author at, .

For more information concerning shortwave radio propagation, see and the ARRL Technical Information
Service web page at, at
For an explanation of numbers used in this bulletin, see

An archive of past propagation bulletins is at More good
information and tutorials on propagation are at

Instructions for starting or ending email distribution of ARRL
bulletins are at .

Sunspot numbers for April 29 through May 5, 2021 were 37, 35, 11, 0,
0, 0 and 0, with a mean of 11.9. 10.7 cm flux was 76.9, 72.9, 71.6,
72, 71.6, 70.6, and 69.5, with a mean of 72.2. Estimated planetary A
indices were 5, 15, 10, 20, 14, 8, and 3, with a mean of 10.7.
Middle latitude A index was 4, 15, 10, 16, 12, 8, and 4, with a mean
of 9.9.


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