SB PROP @ ARL $ARLP012
ARLP012 Propagation de K7RA

ZCZC AP12
QST de W1AW
Propagation Forecast Bulletin 12 ARLP012

From Tad Cook, K7RA

Seattle, WA March 24, 2023
To all radio amateurs

SB PROP ARL ARLP012
ARLP012 Propagation de K7RA

Sunspot numbers were lower again this week, with the average
declining from 143.6 two weeks ago to 118.7 last week and now 68
this week. Average daily solar flux sank 8 points from 153.6 last
week to 145.6.

Six new sunspot groups emerged over the week, one on March 17,
another March 18, three more on March 19, one more on March 21 and
another on March 22.

Predicted solar flux is 150, 145 and 145 on March 24-26, 150 on
March 27-28, 145 and 150 on March 29-30, 138 on March 31 through
April 1, then 136, 136 and 134 on April 2-4, 132 on April 5-7, 130
on April 8-9, then 132, 135, 138, and 140 on April 10-13, 142 on
April 14-15, 143 on April 16, 140 on April 17-18, 142 on April
19-21, and 144 on April 22, 146 on April 23-24, 142 and 140 on April
25-26, 138 on April 27-28, and 136 on April 29-30.

Predicted planetary A index is 35, 30, 20, 15 and 10 on March 24-28,
8 on March 29-30, then 18, 12, 12, 10 and 8 on March 31 through
April 5, 5 on April 6-9, then 15, 12, 8 and 5 on April 10-13, 8 on
April 14-15, then 12, 10, 5 and 5 on April 16-19, then geomagnetic
unrest returns with 10, 36, 20, 10, 8 and 5 April 20-25, then 20,
18, 12, 12 and 10 on April 26-30.

On Thursday, Spaceweather.com reported, "The forecast did not call
for this. During the early hours of March 23rd, a crack opened in
Earth's magnetic field, and stayed open for more than 8 hours. Solar
wind poured through the gap to fuel a strong G3-class geomagnetic
storm."

I watch this site frequently looking for disturbances when
propagation seems odd:

https://www.swpc.noaa.gov/products/planetary-k-index

On Thursday it showed estimated planetary K index at 7, then
dipping, and at 2100 UTC above 7. I noticed some very odd
propagation. At 1900 UTC I called CQ on 10 meter FT8, and
pskreporter.info showed I was only being heard in a small area in
east Texas. Stations were concentrated between 1739 and 1892 miles
in an area between Houston, San Antonio, Killeen and Nacogdoches.
That was it! Heard nowhere else. I was running low power, using a
simple end-fed one wavelength wire that is mostly indoors.

Over the next half hour coverage extended east to Louisiana, then
Alabama, then Georgia and South Caroline.

At 1950 UTC I went to 15 meters, and noticed a similar oddity, this
time with stations in an arc between 1510-2680 miles, bordered by
N1AC in Florida, NT5EE in Texas, KI5WKB in Oklahoma and a station in
North Carolina.

A check again at 0050 UTC last night on 15 meter FT8 and
pskreporter.info showed for over and hour the only stations I was
receiving were two Cubans, and the only stations hearing me were in
an arc from Arizona to Alabama.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - March 23, 2023 from F.K. Janda, OK1HH.

"If we were to assess solar activity in the last seven days by the
number and size of sunspots, or by the number of energetic flares,
it would not seem significant. Yet it was, but we only know that
because of satellite observations. For example, NASA's SDO
observatory recorded a dark plasma eruption at 0630 UTC on 17 March.

"The speed of the solar wind began to increase on 21 March. Far more
noticeable was a large coronal hole in the southern hemisphere of
the Sun near the central meridian. The assumption of a strong solar
plasma flow from its borders pointed to a probable disturbance on
March 24.

"But the flow was faster. We saw a really strong geomagnetic storm a
day earlier, on March 23. During the morning hours, the
concentration of free particles around the Earth began to rise
rapidly, as a reliable precursor of the coming storm. The
geomagnetic disturbance reached a planetary K index of 7 in the
afternoon, so its intensity was rated G3.

"Earth's ionosphere responded to the storm with an increase in MUF
during 23 March. Since the disturbance should continue, albeit with
less intensity, we expect initially below-average shortwave
propagation conditions and then a slow return to average."

Another great video from Dr. Tamitha Skov, WX6SWW:

https://youtu.be/bG0zCbXukm4

This weekend is the CQ World-Wide SSB WPX Contest. See
https://cqwpx.com for info and rules. This is a big, fun contest in
which callsign prefixes are the multiplier.

Send your tips, reports, observations, questions and comments to
k7ra@arrl.net. When reporting observations, don't forget to tell us
which mode you were operating.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information
Service at http://arrl.org/propagation-of-rf-signals . For an
explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good
information and tutorials on propagation are at http://k9la.us/ .

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for March 16 through 22, 2023 were 84, 58, 35, 73,
75, 70, and 81, with a mean of 68. 10.7 cm flux was 135.4, 134.2,
140.3, 142.7, 156.1, 151.6, and 158.9, with a mean of 145.6.
Estimated planetary A indices were 8, 7, 8, 10, 13, 8, and 17, with
a mean of 10.6. Middle latitude A index was 6, 7, 6, 8, 10, 8, and
14, with a mean of 8.4.
NNNN
/EX


--- MBSE BBS v1.0.8 (Linux-x86_64)
* Origin: American Radio Relay League (3:633/280.2@fidonet)

SB PROP @ ARL $ARLP012
ARLP012 Propagation de K7RA

ZCZC AP12
QST de W1AW
Propagation Forecast Bulletin 12 ARLP012

From Tad Cook, K7RA

Seattle, WA March 22, 2024
To all radio amateurs

SB PROP ARL ARLP012
ARLP012 Propagation de K7RA

Over March 14-20, new sunspot groups emerged every day except March
19. March 18 had two, and each of the other days saw one new sunspot
group.

It is now Spring in the Northern Hemisphere which is favorable to HF conditions, and solar and geomagnetic numbers both show improvement.

Average daily sunspot numbers rose from 82.3 to 94.3, and average
daily solar flux jumped from 130.4 to 153.3.

Geomagnetic indicators were very quiet, with the average daily
planetary A index dropping from 8.9 to 5.9, and middle latitude
numbers from 7 to 5.

Here is the outlook for the next month.

Predicted solar flux is 180 and 178 on March 22-23, 174 on March
24-25, then 176 on March 26-27, 178 on March 28, 165 on March 29-30,
160 on March 31, 155 on April 1-3, then 158 on April 4, 160 on April
5-6, then 162, 155, 150, and 145 on April 7-10, 148 on April 11-12,
then 152, 155, 160, 162, 165 and 160 on April 13-18, then 155 on
April 19-20, 152 on April 21, 160 on April 22-23, then 162, 165, 165
and 160 on April 24-27, and 155 on April 28-30.

Predicted planetary A index is 12, 5, 16, 18 and 8 on March 22-26,
then 5, 5 and 8 on March 27-29, 5 on March 30 through April 2, then
15, 12 and 12 on April 3-5, 5 on April 6-8, 8 on April 9-11, then 5
on April 12-23, 10 on April 24-25, and 5 on April 26-29.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - March 21, 2024, from F.K. Janda, OK1HH:

"Solar activity on average continues to increase toward the Solar
Cycle 25 maximum. This included a shower of protons that came from
the admittedly smaller in X-ray intensity but primarily long-lived
flare on the morning hours UTC of March 15. The particle density
peaked a day later when the proton event reached S1. High polar cap
absorption of radio waves was recorded at the same time.

"The geomagnetic field remains mostly calm, with the occurrence of
short active intervals. An increase in geomagnetic activity was
expected after the eruption of 17 March. A partial CME halo was
observed and ejected particles were expected in the vicinity of the
Earth first on 20 March, then on the evening of 20 March, and then
on the morning of 21 March. The result was an increase in MUF
already in the forenoon UTC. An increase in the Earth's magnetic
field activity occurred in the afternoon.

"The new sunspot group AR3615, which emerged in the southeast of the
solar disk, although not yet large, has a complex magnetic
structure. This configuration increases the probability of magnetic reconnection during a solar flare. Especially if an X-class solar
flare occurs, the probability of CME will increase."

Angel Santana, WP3GW wrote about conditions on March 16 in an email:

"With much expectation worked the Russian DX contest on SSB, but
then noticed rough conditions, so bad that after 1600 UTC signals
were gone, not seen on my radio. After 1730 UTC saw them come back
but conditions were still bad.

"Next day did the BARTG RTTY contest after 1430 UTC and fared
better.

"Did it have to do with one of the six sunspots last week? Hope prop
is good in a week from now."

I replied that according to Spaceweather.com, departing sunspot
AR3599 blasted protons toward Earth on March 14, causing a polar cap
absorption event on March 16. The ionizing effect of the protons
absorbed radio signals inside the arctic circle.

Nasa Space Flight article about VLA detection of radiation above
sunspots:

https://bit.ly/4cDDref

Article about Radio Blackout:

https://bit.ly/3ILT6KH

From Dr. Tamitha Skov, WX6SWW:

"Dear Tad,

"Recently our Sun gave us a surprise when a solar storm we thought
would be a glancing blow, actually hit us pretty hard. That was back
on March 3rd and some gorgeous aurora shows were seen in Tasmania
and Australia (see my forecast from that week for some amazing
pictures: https://youtu.be/2nWLAYL01FA).

"Here we are several weeks later with yet another glancing blow set
to hit us midday March 20th. The official forecast is calling for a
weak impact, but our recent experience has left me wondering: Are we
are going to make the same mistake twice?

"These are the kinds of dilemmas that make space weather such a
tough field today. Compared to terrestrial weather, there are so
many things we simply cannot foresee.

"Turning to the forecast, big flare activity is beginning again
thanks to old Region 3590 rotating back into view along with some
new players as well. Amateur radio bands are getting noisier and
radio blackouts are resuming on the daylight side of Earth. Of
course, the big story is the solar storm coming towards us. Will it
be relatively mild at mid-latitudes, as the predictions suggest?
This time, I'm not so sure. Either way, I will remain on the
lookout.

"Cheers, Tamitha."

Here is her latest video report:

https://youtu.be/O6vZDFaBfrc

Send your tips, reports, observations, questions, and comments to k7ra@arrl.net. When reporting observations, don't forget to tell us
which mode you were operating.

For more information concerning shortwave radio propagation, see http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals . For
an explanation of numbers used in this bulletin, see http://arrl.org/the-sun-the-earth-the-ionosphere .

An archive of past propagation bulletins is at http://arrl.org/w1aw-bulletins-archive-propagation . More good
information and tutorials on propagation are at http://k9la.us/ .

Also, check this QST article about Solar Indices:

https://bit.ly/3Rc8Njt

Instructions for starting or ending email distribution of ARRL
bulletins are at http://arrl.org/bulletins .

Sunspot numbers for March 14 through 20 2024 were 88, 49, 67, 86,
127, 123, and 120, with a mean of 94.3. 10.7 cm flux was 127.1, 129,
144.1, 151.3, 177.4, 168.9, and 175.5, with a mean of 153.3.
Estimated planetary A indices were 8, 8, 3, 3, 6, 9, and 4, with a
mean of 5.9. Middle latitude A index was 7, 8, 3, 2, 5, 7, and 3,
with a mean of 5.
NNNN
/EX


--- MBSE BBS v1.0.8.4 (Linux-x86_64)
* Origin: American Radio Relay League (3:633/280.2@fidonet)