Register Account

Login Help

ARRL Propagation Bulletin ARLP013 (2019)

ARLP013 Propagation de K7RA

QST de W1AW  
Propagation Forecast Bulletin 13  ARLP013
From Tad Cook, K7RA
Seattle, WA  March 29, 2019
To all radio amateurs 

ARLP013 Propagation de K7RA

During our reporting week (March 21-27) solar activity increased
while geomagnetic indicators were lower, compared to the previous
seven days. This is a nice combination for the first week of spring.

Although sunspots and solar flux decreased toward the end of the
period, average daily sunspot numbers doubled from 8 to 16, and
average daily solar flux increased from 70.7 to 75.2.

Average daily planetary A index decreased from 8.1 to 3.7, and
average daily middle latitude A index decreased from 6.3 to 3.9.

These numbers are all good, because higher sunspot numbers and solar
flux suggest better enhancement of the ionosphere while the lower
geomagnetic numbers correspond to generally lower absorption or
disturbed conditions.

The planetary A index is a composite from magnetometers around the
globe, but the middle latitude A index is from a single magnetometer
in Virginia.

Predicted solar flux from the March 28 forecast is 68 on March 29
through April 4, 70 on April 5-6, then 71 and 74 on April 7-8, 75 on
April 9-18, then 74, 73, 73 and 71 on April 19-22, 70 on April 23
through May 3, 71 and 74 on May 4-5, and 75 on May 6-12.

Predicted planetary A index is 12 on March 29, 8 on March 30 through
April 2, 6 and 8 on April 3-4, 5 on April 5-11, then 15 and 10 on
April 12-13, 5 on April 14-21, then 8, 12, 12, 8 and 8 on April
22-26, 5 on April 27-28, 8 on April 29-30, 5 on May 1-8, then 12, 8,
5 and 5 on May 9-12.

The above predictions for solar flux and A index are updated daily
at, .

There have been no sunspots on March 26-28. Here is an image of
sunspot group AR2736 from March 23, a few days before it

From F.K. Janda, OK1HH.

"Geomagnetic activity forecast for the period March 29 til April 27,

"Geomagnetic field will be:
Quiet on March 31, April 11, 16, 18-21, 27
Quiet to unsettled on March April 1-4, 11-12, 22, 25-26
Quiet to active on March 30, April 6-10, 15, 23-24
Unsettled to active on March 29, April 5, 13-14, 17

"Solar wind will intensify on March 29 (- 30), April (2-6,) 12-13,

"Parenthesis means lower probability of activity enhancement."

NN4X reported:

"12M 3/28/2019

"I decided to call CQ into a 'dead' band, and soon saw showing I was heard in EA8. I continued calling and
soon had QSOs with EA8, PY, KP4 and LU, and was heard in France and

"17M 3/26/2019

"Looking for E6, I worked VK2FR, VK6YM, VK4EM and ZL3NB instead on a
seemingly dead band. I worked E6 on 3/27 at 21:41Z.

"I wish more folks would occasionally let loose with some CQs, to
determine if we have any propagation.

"12M opened up again after my previous e-mail.

"Additional countries worked included EA6, F, ZD7 and YV. I heard
CT, and the opening extended into EU.

"I had to leave after 5:00 PM local so was not able to look west for
any late afternoon/early evening openings, although I don't see
anything posted to DX Cluster.

"Once again, it pays to make some noise; you never know who's
listening, or where."

The CQ World Wide WPX SSB Contest is this weekend.


The latest from Dr. Tamitha Skov, WX6SWW:

"Dear Tad,

"What happened nationwide this past week was a tragedy-- it did not
need to happen. It's always personally painful to me when some
members of the media spot a 'solar storm opportunity.' Without
thinking, they jump on these storms and hype them beyond
recognition. Seduced by the allure of aurora views and a world of
science-fiction adventure, people from all over then embark on a
solar storm crusade. They pack their bags, and their cars, and head
hundreds of miles towards the poles singing victory songs with stars
in their eyes. Their trip begins with enthusiasm, awe, and wonder,
but it ends tragically. It leaves many feeling confused and left out
in the dark and cold (literally) as they look skyward for an aurora
show that never comes.

"Events like these are stark reminders of why it's so critical we
continue to push forward to create a field of Space Weather
broadcasting. When the media runs amok, omitting critical aspects of
Space Weather that make forecasting so difficult and aurora so
elusive, it traps everyone in its web. You, me, and especially the
uninitiated. But there is a bright spark I am beginning to see. Far
more than ever before, I saw this community push back on the hype.
What is more-- I watched as journalists and meteorologists alike,
learned from us.  As in the picture above, I saw proof we are
winning the battle. We are slowly pushing back against the media
veil that continues to keep Space Weather shrouded in mystery. I
know a huge part of our success is due to you, and I am eternally

"As for this week's forecast, our Sun calms down a bit as rogue
region 2736 rotates to the Sun's backside. We won't see it again for
another two weeks. This means emergency, shortwave, and amateur
radio propagation tanks again on Earth's day side, even as GPS
reception improves. We also get another chance for a solar storm
from a small pocket of fast wind that is already brightening the
aurora again. So at least that is good news for aurora hopefuls, who
missed out on the show this past week. Too bad no media are
reporting on the aurora viewing chances now. They're actually better
than during the peak of the hype. So much for a fizzle and a frenzy.
"Cheers, Tamitha."

Her latest video is, .

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

For more information concerning radio propagation, see the ARRL
Technical Information Service web page 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

Monthly propagation charts between four USA regions and twelve
overseas locations are at

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

Sunspot numbers for March 21 through 27, 2019 were 49, 27, 22, 14,
0, 0, and 0, with a mean of 16. 10.7 cm flux was 80.1, 82.4, 79.4,
75.4, 71.2, 69, and 68.9, with a mean of 75.2. Estimated planetary A
indices were 2, 1, 1, 3, 5, 6, and 8, with a mean of 3.7. Middle
latitude A index was 2, 2, 2, 3, 5, 5, and 8, with a mean of 3.9.


Instragram     Facebook     Twitter     YouTube     LinkedIn