SB PROP @ ARL $ARLP015
ARLP015 Propagation de K7RA

ZCZC AP15
QST de W1AW
Propagation Forecast Bulletin 15 ARLP015

From Tad Cook, K7RA

Seattle, WA April 14, 2023
To all radio amateurs

SB PROP ARL ARLP015
ARLP015 Propagation de K7RA

Solar activity was up for this reporting week, April 6-12.

Seven new sunspot groups appeared, one on April 6, another on April
9, two more on April 10, another on April 11, and two more on April
12. Then on Thursday, April 13, three new sunspot groups emerged.
The sunspot number rose to 154, the highest value in the past month.

Average daily sunspot number rose from 53.4 to 70.6, and average
daily solar flux increased from 132.5 to 141.

On Thursday, the noon solar flux reading was 159.5 and was well
above the average for the previous seven days, perhaps indicating an
upward trend.

Geomagnetic conditions were calm, with average daily planetary A
index dropping from 15 to 7.6, and the middle latitude average from
11.7 to 6.4.

Predicted solar flux was 155 and 160 on April 13-14, and 165 on
April 15-16.

The Thursday prediction was well above that.

Predicted solar flux is 168 on April 14-16, 165 and 160 on April
17-18, 155 on April 19-22, 158 on April 23, 155 on April 24-25, then
152, 148, 145 and 142 on April 26-29, 140 on April 30 and May 1, 142
and 140 on May 2-3, 135 on May 4-5, then 130, 140, 145, 150, 152,
155 and 158 on May 6-12, then 160 on May 13-15, and 150 and 152 on
May 16-17, 155 on May 18-19, then 158, 155 and 155 on May 20-22.

Predicted planetary A index is 8, 12, 10 and 8 on April 14-17, 5 on
April 18-20, then 8 and 10 on April 21-22, 5 on April 23-25, then 15
and 18 on April 26-27, 15 on April 28-30, then 12 and 10 on May 1-2,
8 on May 3-4, 5 on May 5-6, then 8, 10 and 8 on May 7-9, and 5 on
May 10-13, then 10, 15 and 5 on May 14-16, 20, 15 and 10 on May
17-19, and 5 on May 20-23.

Spaceweather.com released this news on Wednesday:

"Evidence is mounting that Solar Cycle 25 might peak much earlier
than expected. New research by a leading group of solar physicists
predicts maximum sunspot activity in late 2023 or early 2024 with a
peak that could be twice as strong as the previous solar cycle."

Look in the Spaceweather archive for April 12-13 to read more. It
is all explained in this scientific paper:

https://bit.ly/41gZnW4

I noticed some very odd 10 meter propagation at 2000 UTC on April
11. Running FT8 and a one wavelength end fed wire at my home in
Seattle, the only stations that heard me according to
pskreporter.info were one in New Zealand, another in Hawaii, and in
North America, only 5 stations (NK5B, AD4ES, K4RMM, KB4FB and AA4CB)
in Florida, all within a 200 mile strip from 2,512 to 2,712 miles
from me. Checking again at 2015 UTC, it was still the same. It
looked quite dramatic on the pskreporter.info map.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - April 13, 2023, from F.K. Janda, OK1HH.

"Relatively frequent C-class solar flares, sporadic M-class flares
in one or two sunspot groups, and the appearance of two or three
relatively small coronal holes - that's how the Sun looked between
April 6 and 13.

"The solar wind speed dropped to 340 km/s by April 9, rose
significantly to 550 km/s on April 10, and then slowly dropped
again. The Earth's magnetic field was unsettled on April 10, then
mostly calm on the other days.

"MUF values were slightly higher on 10 April. This was followed by
11 April with irregular daily MUF and irregular occurrences of
attenuation. Since 12 April onward there was a transition to a
regular daily course of ionospheric parameters.

"Now we can expect higher solar activity in the southern hemisphere.
The rise should continue in the coming days at first. A slight
decrease will follow after the weekend.

"A slight increase in geomagnetic activity with consequent
fluctuations in shortwave propagation conditions can be expected
rather since the middle of next week."

Here is a video about the Termination Event:

https://youtu.be/wcJdNBow_5s

A story on NASA using AI to predict geomagnetic storms:

https://bit.ly/3mws16y

Here is a story about Radio Blackout:

https://bit.ly/3UCz8ar

Mike Mason, WB4MM in Daytona Beach, Florida wrote:

"On April 9 2023 FT8 mode 12 meters beginning at 2254 UTC and ending
at 2328 UTC I worked 12 JA stations plus 2 South Korean stations in
a row. I was calling CQ AS WB4MM EL99.

"My station has 100 watts to an attic 15M dipole. I believe the SFI
at the time was 135. Not sure of the type of prop. This occurred
within an hour of sunset at my QTH."

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 April 6 through 12, 2023 were 33, 38, 49, 52,
92, 103, and 127, with a mean of 70.6. 10.7 cm flux was 137.1,
136.3, 135.9, 140.3, 139.8, 143.4, and 154, with a mean of 141.
Estimated planetary A indices were 9, 8, 6, 6, 14, 6, and 4, with a
mean of 7.6. Middle latitude A index was 7, 7, 5, 5, 11, 6, and 4,
with a mean of 6.4.
NNNN
/EX


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

SB PROP @ ARL $ARLP015
ARLP015 Propagation de K7RA

ZCZC AP15
QST de W1AW
Propagation Forecast Bulletin 15 ARLP015

From Tad Cook, K7RA

Seattle, WA April 12, 2024
To all radio amateurs

SB PROP ARL ARLP015
ARLP015 Propagation de K7RA

I did not see last Monday's eclipse, except on television. Here in
the Pacific Northwest, we only got a 20% exposure, and skies were
overcast.

As they moved across the country displaying successive totality, I
noticed the prominences on the edge of the disk. There were always
between one and three little red spots at the edge.

Solar activity over the past reporting week, April 4-10, remains
weak.

Average daily sunspot number rose from 60 to 67.9, but average solar
flux declined from 136.9 to 123.2.

Seven new sunspot groups emerged this week, one on April 4, three on
April 5, another on April 6, one more on April 8, and another on
April 10.

Here is the outlook for the next few weeks, which does not seem
promising. Solar flux peaks at 160 over April 17-18.

Predicted solar flux is 148, 150 and 155 on April 12-14, 158 on
April 15-16, 160 on April 17-18, 140 on April 19-20, 135 on April
21-22, 140 and 145 on April 23-24, 140 on April 25-26, then 135, 125
and 120 on April 27-29, and 125 on April 30 through May 10, then 130
on May 11-12, 135 on May 13-14, and 130 on May 15-18.

Predicted planetary A index is quiet over the next month, starting
with 5, 8, 15, 10 and 8 on April 12-16, 5 on April 17-18, 8 and 10
on April 19-20, 8 on April 21-23, 5 on April 24-27, then 8, 8 and 7
on April 28-30, 10 on May 1-3, 5 on May 4-5, 8 on May 6-8, and 5 on
May 9-15, then 8 and 10 on May 16-17, and 8 on May 18-20.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere - April 11, 2024, from F.K. Janda, OK1HH:

"At the end of March, it was still possible to see large sunspot
groups, during the last solar rotation marked as AR3614 and
especially the giant AR3615. We will see them again on the eastern
limb of the solar disk this weekend. This will end a roughly
two-week period of relatively quiet solar activity without major
solar flares.

"The Sun's total X-ray output, which has dropped by almost an order
of magnitude, will increase significantly, which will have a
beneficial effect on shortwave propagation.

"Daily MUF values will gradually increase, while active regions will
be on the eastern half of the solar disk. For that reason, here will
be little probability of major geomagnetic disturbances. Of course,
now that the peak of the 11-year cycle is approaching, events such
as the eruption of solar plasma filaments that could affect the
Earth cannot be ruled out."

Douglas Barbier, N8ZVT, wrote in an email:

"Why is the solar flux so low, given the number of sunspots? What
else may be affecting the solar flux?

"This is my first solar maximum as a ham - and at my age, might be
the last. I had always heard stories of how 10m would be open 24
hours a day for voice and working all over the world with low power
SSB. Sure haven't seen that yet at all."

I replied:

"That was nearly 70 years ago at the peak of Solar Cycle 19 when 10
meters was open 24/7.

"There has never been a similar solar cycle since the dawn of radio.
It was all AM back then, no SSB.

"Solar flux readings come from an observatory in Penticton, BC:

"https://www.spaceweather.gc.ca/forecast-prevision/solar-solaire/solarflux/sx-5-flux-en.php

"I have not noticed that solar flux was low.

"Because Earth is in an elliptical orbit around the Sun, a variation
in distance affects solar flux.

"That is why you will see adjusted values in the flux readings from
Penticton.

"You can get a graphic view of sunspot numbers and solar flux from
the WA4TTK solar data plotting utility at:

"http://www.craigcentral.com/sol.asp

"You can update the data automatically using data from this weekly
bulletin."

Solar cycles explained:

https://www.snexplores.org/article/explainer-solar-cycle

A solar cycle clock:

https://www.nature.com/articles/s41598-024-58960-5

Flares during eclipse:

https://bit.ly/3VRBxk0

Prominences, not flares:

https://bit.ly/49waWMC

Solar Cycles:

https://bit.ly/3PY4F5p

Internet apocalypse due to solar storms:

https://bit.ly/3vBW69C

Dr. Tamitha Skov, WX6SWW, reports during the eclipse:

https://youtu.be/Z16_Uk1vym8

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 April 4 through 10 2024 were 47, 81, 71, 79, 79,
64, and 54, with a mean of 67.9. 10.7 cm flux was 113.7, 120.5,
122.9, 124.6, 124.8, 124.4, and 131.2, with a mean of 123.2.
Estimated planetary A indices were 12, 12, 10, 6, 8, 11, and 8, with
a mean of 9.6. Middle latitude A index was 33, 10, 8, 5, 8, 10, and
7, with a mean of 11.6.
NNNN
/EX


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