| SB PROP @ ARL $ARLP044
ARLP044 The ARRL Solar Report
ZCZC AP44
QST de W1AW
Propagation Forecast Bulletin 44 ARLP044
From ARRL Headquarters
Newington, CT, November 21, 2025
To all radio amateurs
SB PROP ARL ARLP044
ARLP044 The ARRL Solar Report
Solar activity has remained low this past week. The largest flare was a C9.9 on November 19 from a region just beyond the NE limb near N17. Region 4284 grew slightly in the early part of the period but was in decay after November 19.
New Region 4287 was numbered. A Type II radio sweep (estimated at 695 km/s) was observed on November 19 at 2215 UTC, likely associated with a B9.0 flare from just beyond the east limb. No Earth-directed CMEs were observed. Solar activity is expected to be at low levels, with a slight chance for moderate levels (R1-R2/minor-moderate) to November 21.
Solar wind parameters were at nominal levels. Solar wind speed ranged from 346 – 421 km/s. Total field ranged from 4-8 nT while the Bz component was between +8/-2 nT. Phi angle was predominantly negative. By late November 20, a negative polarity coronal hole high-speed stream (CH HSS) is expected to become geoeffective, causing a minor enhancement in the solar wind.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s Ionosphere, November 20, 2025, by F. K. Janda, OK1HH:
“Solar activity over the last three months has fluctuated fairly regularly within an approximately 27-day period, determined by the rotation of the Sun. The positions of active longitudes do not change much, which makes it relatively easy to predict not only solar but also geomagnetic activity. However, we are still close to the 11-year maximum, so the large solar flares on November 9, 10, and 11 were not a major surprise.
“However, the fact that the coronal plasma clouds from the first two flares merged (the second, faster one caught up with the first) and caused a massive geomagnetic disturbance on November 12 could have been a surprise.
“The massive disturbance lasted only until November 13, followed by alternating calm days on November 14-15 and November 18-19 with turbulent days, for which a more accurate forecast was not possible. We are likely to see an increase in solar activity during the third 3rd of November and the first 3rd of December, with increased geomagnetic activity most likely expected in the last days of November and the first days of December. However, the regularity of fluctuations in solar and geomagnetic activity will end during this period, while it is advisable to pay attention to newly emerging active regions and the shift of coronal holes on the Sun.”
High Speed Stream activity is expected to wane through November 22. Solar wind speeds in the 450-550 km/s range are likely based on recurrent values. The geomagnetic field is likely to reach unsettled conditions on November 22 due to waning solar wind enhancements. Mostly quiet conditions are expected on November 23.
Spaceweather.com for November 21 reports that Sunspot 4274, which caused the Veteran’s Day aurora and radiation storm, will be back after Thanksgiving.
The latest video report from Dr. Tamitha Skov, WX6SWW, can be found on YouTube at https://www.youtube.com/watch?v=FOLDm_N6ft8.
The current Solar Cycle Progression from the NOAA/Space Weather Prediction Center can be found at www.swpc.noaa.gov/products/solar-cycle-progression.
The Predicted Planetary A Index for November 22 to 28 is 8, 5, 15, 18, 25, 20, and 10, with a mean of 14.4. Predicted Planetary K Index is 3, 2, 4, 5, 5, 5, and 3, with a mean of 3.9. 10.7-centimeter flux is 110, 105, 110, 110, 110, 120, and 130, with a mean of 113.6.
For more information concerning shortwave radio propagation, see www.arrl.org/propagation and the ARRL Technical Information Service 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
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