SB PROP @ ARL $ARLP010
ARLP010 The ARRL Solar Report

ZCZC AP10
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 activity. The largest event of the period was a C2.9 flare from Region 4381 on March 3. Region 4384
continues to rotate further onto 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 Earth-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 March 6.


A brief description of Sunspots can be found on the Space Weather Prediction Center website at www.swpc.noaa.gov/phenomena/sunspotssolar-cycle [ https://www.swpc.noaa.gov/phenomena/sunspotssolar-cycle ] .


Solar wind parameters reflected the onset of a positive polarity coronal hole high-speed stream (+CH HSS). Solar wind speed increased 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 magnetic 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 shortwave 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 second 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 at normal to moderate levels.


Geomagnetic field activity is expected to range from quiet to G2 (Moderate) geomagnetic storm levels. Active conditions are likely 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 March 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 [ 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 Index 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 [ http://www.arrl.org/propagation?utm_source=Informz&utm_medium=Email&utm_campaign=ARRL
] and the ARRL Technical Information Service web page at www.arrl.org/propagation-of-rf-signals [ http://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 [ http://arrl.org/the-sun-the-earth-the-ionosphere ] . Information and
tutorials on propagation can be found at http://k9la.us [ http://k9la.us/ ] .


Also, check this: "Understanding Solar Indices" from September 2002 QST. https://bit.ly/3Rc8Njt [ https://bit.ly/3Rc8Njt ]

NNNN
/EX

ARRL The National Association for Amateur Radio(R)


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