SB PROP @ ARL $ARLP024
ARLP024 Propagation de K7RA
QST de W1AW
Propagation Forecast Bulletin 24 ARLP024
From Tad Cook, K7RA
Seattle, WA June 16, 2023
To all radio amateurs
SB PROP ARL ARLP024
ARLP024 Propagation de K7RA
At 2256 UTC on June 16 the Australian Space Weather Forecast Centre
issued a geomagnetic warning: "The solar wind speed on UT day 15-Jun
has increased as the Earth entered a coronal hole wind stream after
15/0545UT. Increased geomagnetic activity is expected for 16-Jun
with isolated periods of G1-Minor level activity."
Earlier in the day I checked the NOAA planetary K index page, and it
showed a jump from K index of about 1.8 at 1200 UTC to about 4.1 at
1500 and again at 1800 UTC, then about 4.5 at 2100 UTC and 5.5 at
0000 UTC on June 16. At 0300 UTC it was down a bit to 5.
See, https://www.swpc.noaa.gov/products/planetary-k-index .
Solar activity declined this week, with average daily sunspot
numbers dropping from 139 to 122, while average daily solar flux
decreased from 166.8 to 154.8. This compares the current reporting
week of June 8-14 against the previous seven days.
Average daily planetary A index decreased from 7.3 to 5.7, and
average daily middle latitude A index from 8.6 to 6.7.
On June 14 Spaceweather.com reported two new sunspot groups emerging
across the Sun's southeastern horizon.
Forecasters Cundiff and Trost of the U.S. Air Force 557th Weather
Wing predict solar flux at 155 on June 16-17, 160 on June 18-19,
then 155, 160 and 165 on June 20-22, 170 on June 23-25, then 168,
165 and 162 on June 26-28, 160 on June 29 through July 4, 165 on
July 5, 170 on July 6-8, then 155, 157, 153 and 160 on July 9-12,
150 on July 13-14, 155 on July 15-17, then 160 and 165 on July
18-19, and 170 on July 20-22.
Predicted planetary A index is 18, 12 and 8 on June 16-18, 5 on June
19-20, 8 on June 21-22, 5 on June 23-26, 12 on June 27-28, 5 on June
29-30, then 12 and 8 on July 1-2, 5 on July 3-7, 12 on July 8-10,
then 5, 5, and 12 on July 11-13, and 10 on July 14-15, and 5 on July
These predictions look great for ARRL Field Day, which is June
24-25. Why? Solar flux peaks at 170 on June 23-25, and the predicted
planetary A index is a nice quiet 5 on June 22-26. Next week we will
present an updated forecast just prior to Field Day weekend.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere June 16 - June 22, 2023 from F.K. Janda, OK1HH.
"The first half of June was quieter than May, both on the Sun and in
the Earth's magnetosphere and ionosphere.
"However, helioseismic maps of the far side of the Sun showed a
number of large active regions, probably sunspots. We therefore
expected an increase in activity. But that's not likely to happen
until a week from now.
"Even so, there were some rather unexpected eruptions of moderate
magnitude during the local midday, which triggered a SWF (Shortwave
Fading) that could have broken the QSO in the longer half of the
"Meanwhile, we observed a coronal hole in the solar equator region
that crossed the central meridian on June 12.
"Associated with it is the co-rotating interaction region (CIR),
which are the transition zones between the slow and fast solar wind
streams. Since the accumulation of solar plasma in the solar wind
results in structures that are similar to the arrival of a CME, we
expected a geomagnetic storm on the evening of 15 June UTC. The
estimate was quite accurate - the disturbance began at 1500 UTC.
"We can expect the geomagnetic field to be active for a few more
days, including smaller storms."
"It was great on 6m last weekend. I was only on SSB on 6m, but I
understand it was open all over on FT8. I believe the openings were
caused by summer E-skip, not F2. I worked many, many stations in
your grid square. Roger K6LMN in DM04sb Los Angeles."
He sent this to N0JK:
"We on the West Coast were finally treated to some decent E-skip on
6 meters SSB and CW (do not know about FT8). The June VHF Contest
was just great Saturday and Sunday afternoons into early evening,
Pacific Daylight time. Before this contest the band out here has
been fairly quiet.
"So briefly, I was K6LMN/Limited Rover in DM03 DM04 all around LA.
I had a tight schedule with many social engagements plus two
funerals to attend. I could not get too serious with heavy artillery
or going to 5,000+ ft. mountaintops. For 6m I simply used my Larsen
5 ft. magmount on the car roof. The rig was my old IC-706IIG with
only 90 watts SSB. I was also on 2m, 1-1/4m, and 70 cm.
"Most DX contacts were on both days up to Oregon, Washington, Idaho,
Montana, BC, and Alberta. But the surprise was Sunday early evening.
Best 2 way DX was N9XG in EN60 (Indiana) and K9CT in EN50 (Illinois)
with 1 hour to go before contest close. They were like 5 by 5 on
peaks on SSB. I am sure all this big DX was double hop summer
"A surprise was VA6AN way up in Canada popping in/out on SSB with
peaks up to 5 by 5 Sunday eve about 6:30 pm local time. However, the
QRM was horrible (my whip is omnidirectional) so he did not work me.
"I worked K7YO up in CN85 (his alternate QTH) and he said he was
getting into Florida on SSB or CW or FT8 on 6M. Maybe triple hop
"I am unhappy that us West Coasters are not getting any F2 so far on
6m in Solar Cycle 25. I am 85 years old, licensed in 1955 and was
lucky to enjoy the all-time best F2 openings on 10m and 6m (AM) back
in the Golden Days in 1956-1958 in Solar Cycle 19. Incredible!"
N0JK sent a note on June 12 that he worked IK5YJY on 6 meter FT8. He
also wrote: "6M Es all weekend and 2M Es Sunday eve for the ARRL VHF
contest. By the way, you had a station (W9NY) comment about poor
conditions on 6M in last week's bulletin. Last weekend was awesome.
I made 3 JA contacts with 10w and a 3 el yagi from KS.
"Today A71VV (Qatar) was in to Northeast KS around 1400z."
Check out the images on the A71VV page on QRZ.com.
Scotty, W7PSK sent a note on June 12 listing countries worked on 6
meter FT8: Balearic Islands, France, Spain, England and Canada.
An image of the International Space Station over a sunspot:
A video too:
A study of the Sun's coldest region:
Another breathless warning from South Asia about flares:
This weekend is the 64th annual CW weekend of the All Asian DX
Contest. See the JARL web site for rules:
Send your tips, reports, observations, questions and comments to
email@example.com. 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
Also, check this article from September, 2002 QST:
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 June 8 through 14, 2023 were 149, 152, 116, 116,
116, 98, and 107, with a mean of 122. 10.7 cm flux was 168.5, 164.3,
161.2, 153.8, 146.1, 146.3, and 143.5, with a mean of 154.8.
Estimated planetary A indices were 5, 4, 5, 9, 6, 6, and 5, with a
mean of 5.7. Middle latitude A index was 6, 6, 4, 10, 8, 8, and 5,
with a mean of 6.7.