SB PROP @ ARL $ARLP009
ARLP009 The ARRL Solar Report

ZCZC AP09
QST de W1AW
Propagation Forecast Bulletin 9 ARLP009

From ARRL Headquarters

Newington, CT February 27, 2026
To all radio amateurs

SB PROP ARL ARLP009
ARLP009 The ARRL Solar Report

Spaceweather.com [ http://Spaceweather.com ] for February 27 reports about a minor CME hurling towards Earth.


Solar activity remains at low levels due primarily to C-class flares just beyond the SE limb near S21. The largest was a C5.3 flare on February 25. On the visible disk, an approximate 5-degree filament eruption was observed centered near S08W27 with an associated C2.6 flare.


The eruption was accompanied by a Type II radio sweep (595 km/s) and possibly two related coronal mass ejections (CMEs), first observed in ST A COR2
imagery beginning on February 25. Two CMEs were observed off the NE and E
limbs in the imagery. However, SOHO/LASCO C2 imagery only showed the
northerly CME. Analysis of the CMEs is in progress.


Solar activity is likely to remain at low levels with a slight chance for isolated M-class activity (R1-R2/minor-moderate), as the bright regions currently seen at the east limb rotate onto the visible disk.


Solar wind parameters continued to show Coronal Hole High Speed Stream (CH
HSS) influence. Solar wind speed ranged from 530-650 km/s. Conditions are likely to return to nominal levels as High Speed Stream activity wanes.


Weekly Commentary on the Sun, the Magnetosphere, and the Earth's Ionosphere, February 26, 2026, by F. K. Janda, OK1HH:


"Between February 22 and 24, there was not a single spot on the solar disk, which last happened less than four years ago. The maximum of the 25th cycle
is behind us, while the years 2024-2025 can be considered the years of cycle maximum.


"At the same time, the Sun is in a key phase of reversing its magnetic field. This process is a natural part of the 11-year solar cycle, usually occurring asymmetrically (the northern and southern hemispheres of the Sun may reverse
at slightly different times, with the process taking several months). The magnetic field in the polar regions of the Sun gradually weakens until it completely breaks down and reforms with the opposite polarity.


"The next eleven-year solar minimum (the transition between the current 25th and future 26th cycles) is expected in 2030-2031, when the Sun's magnetic
field will stabilize again and the star will enter a quiet period. A more precise date for the minimum will only be possible to determine at the end of the decade based on the current development of sunspots.


"During the first week of March, solar activity should gradually increase and then decrease in the following week. Changes in the intensity of the solar
wind will have the greatest impact on the development of shortwave
propagation conditions. For prediction of these changes, it is recommended to monitor the position and area of coronal holes and, in particular, solar
flares that will be located near their edges.


"This can be monitored excellently at www.solarham.com [ https://www.solarham.com/ ] , for example, and even professionals will
confirm that you will find everything you need here to understand the causes
of ongoing events and for operational practice. In addition, we can monitor
the local effects in the ionosphere in detail especially thanks to
ionospheric digisonde stations, dozens of which are available on the
internet!"


Active periods are likely, with a chance for G1 (Minor) storm levels, on February 28 to March 1, due to the anticipated arrival of a CME that left the Sun on February 25.


The greater than 2 MeV electron flux at geosynchronous orbit is expected to reach high levels on March 3, and then on March 6 to 8 due to anticipated influence of multiple recurrent coronal holes.


The latest 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 February 28 to March 6 is 5, 5, 5, 5, 5, 15, and 15, with a mean of 7.9. Predicted Planetary K Index is 2, 2, 2, 2, 2, 4, and 4, with a mean of 2.6. 10.7-centimeter flux is 122, 122, 125, 125,
125, 125, and 130, with a mean of 124.9.


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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