Message:18354 In: PROP.ARL
From: NC8QDate: Fri, 06 Mar 26 18:18:00 Z
Newsgroups: PROP.ARL
Subject: ARLP010 The ARRL Solar Report
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QST de W1AW
Propagation Forecast Bulletin 10 ARLP010
>From ARRL Headquarters
Newington, CT March 6, 2026
To all radio amateurs
SB PROP ARL ARLP010
ARLP010 The ARRL Solar Report
Solar activity continued at low levels with isolated C-class flaring. Regions 4381 and 4384 remained the primary drivers of act
ivity. The largest event of the period was a C2.9 flare from Region 4381 on March 3. Region 4384 continues to rotate further on
to the disk, but foreshortening still hinders a definitive characterization of its magnetic complexity. Region 4378 showed some
new flux emergence but remained mostly inactive.
Region 4383 simplified into a unipolar group following the loss of its trailing spots, while Region 4380 decayed to plage. No E
arth-directed coronal mass ejections (CMEs) were observed in available coronagraph imagery.
Solar activity is expected to be at low levels, with a chance for isolated M-class activity (R1-R2/minor-moderate) through Marc
h 6.
A brief description of Sunspots can be found on the Space Weather Prediction Center website at www.swpc.noaa.gov/phenomena/suns
potssolar-cycle.
Solar wind parameters reflected the onset of a positive polarity coronal hole high-speed stream (+CH HSS). Solar wind speed inc
reased to 450 km/s. Solar wind parameters are expected to remain enhanced due to the ongoing influence of the +CH HSS. Residual
enhancements are likely to persist, keeping conditions slightly above background levels before another enhancement is expected
with the onset of a negative polarity coronal hole high-speed stream (-CH HSS). Active conditions are expected on March 7 and
8 as high-speed stream influences continue.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, March 5, 2026, by F. K. Janda, OK1HH:
"Overall solar activity declined, with the number of sunspot groups ranging between three and six over the past week. Their mag
netic configuration was simple, so no significant flares on the solar disk were observed.
"However, the solar flux remained at a relatively high level of 130-148 s.f.u., which, together with a decrease in geomagnetic
activity (no major disturbances, just alternating calm and moderately active days), resulted in improved conditions for shortwa
ve propagation.
"The current trend is expected to continue for the time being. A change will be caused by a decline in solar activity in the se
cond decade of March. This will be very noticeable in the decline in solar radio flux."
The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on March 8, 11, and 12, and March
15 to 19 due to anticipated influence from multiple, recurrent, CH HSSs. The remainder of the outlook period is likely to be a
t normal to moderate levels.
Geomagnetic field activity is expected to range from quiet to G2 (Moderate) geomagnetic storm levels. Active conditions are lik
ely on March 10, 12, March 14 and 15, and March 20. Unsettled conditions are likely on March 8 and 9, March 11, March 13, and M
arch 16 to 19. All elevated levels of geomagnetic activity are associated with the anticipated influence of multiple, recurrent
, CH HSSs. The remainder of the outlook period is likely to be at mostly quiet levels.
The current solar report from Dr. Tamitha Skov, WX6SWW, can be found on YouTube at https://www.youtube.com/watch?v=6SoYfTnrudc.
The Predicted Planetary A Index for March 7 to 13 is 5, 8, 10, 18, 10, 15, and 10, with a mean of 10.9. Predicted Planetary K I
ndex is 2, 3, 3, 4, 3, 4, and 3, with a mean of 3.1. 10.7-centimeter flux is 156, 156, 150, 145, 140, 135, and 128, with a mean
of 144.3.
For more information concerning shortwave radio propagation, see www.arrl.org/propagation and the ARRL Technical Information Se
rvice web page at www.arrl.org/propagation-of-rf-signals. For an explanation of numbers used in this bulletin, see www.arrl.org
/the-sun-the-earth-the-ionosphere. Information and tutorials on propagation can be found at http://k9la.us.
Also, check this: "Understanding Solar Indices" from September 2002 QST. https://bit.ly/3Rc8Njt
NNNN
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