Solar activity reached moderate levels due to an M1.6 flare on
January 14 from new region AR4341. Spot classification of this
region is complicated by limb proximity and foreshortening effects.
New Region AR4342 rotated around the NE limb and was also numbered.
No Earth-directed Coronal Mass Ejections (CMEs) were observed. Solar
activity is expected to be low with a 25-30% chance for M-class
flares (R1-R2, minor-moderate) to January 17.
Solar wind parameters were elevated under continued negative
polarity coronal hole high speed stream (CH HSS) influences. Solar
wind speed ranged mostly between 450-570 km/s.
Another enhancement in the solar wind is expected early on January
17 when a current, positive polarity, CH HSS is expected to become
geoeffective. Solar wind speed is likely to exceed 700 km/s based on
recurrent data.
The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on January 21 to 27, and then on
January 30 and 31st due to the anticipated influence of multiple,
recurrent coronal holes. The remainder of the outlook period is
likely to be at normal to moderate levels.
Geomagnetic field activity is likely to reach G1 (Minor) geomagnetic
storm levels on January 29, unsettled to active levels on January 19
to 23, and then on 27 and 28. All enhancements in geomagnetic
activity are due to the anticipated influence of multiple, recurrent
Coronal Hole High Speed Streams. The remainder of the outlook
period is expected to mostly quiet.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s
Ionosphere, January 15, 2026, by F. K. Janda, OK1HH:
“Within the 27-day fluctuation, as expected, the solar radio noise
power flux curve on the wavelength of 10.7 cm passed through a
minimum of 111 s.f.u. on January 11. Whereupon began to rise slowly.
The rise will continue, mainly due to new activity around the
southeastern limb of the solar disk, where the currently largest
active region, AR4341, has emerged. Even before its emergence, it
made itself known with M-class solar flares accompanied by CMEs.
“Other significant formations on the Sun include three coronal
holes. The second largest is now located on the northwest part of
the solar disk. The solar wind blowing from its edges is likely to
cause a shorter increase in geomagnetic activity on January 17.
Significantly stronger disturbances can be expected about a week
later, when the large coronal hole will move from the southeast of
the solar disk to the central meridian. This will happen
simultaneously with AR4341, causing a significant increase in solar
flux-and also geomagnetic activity.”
The Predicted Planetary A Index for January 17 to 23 is 5, 5, 18,
15, 12, 8, and 6, with a mean of 9.9. Predicted Planetary K Index
is 2, 2, 4, 4, 4, 3, and 2, with a mean of 3. 10.7-centimeter flux
is 106, 106, 110, 115, 125, 135, and 140, with a mean of 119.6.
For more information concerning shortwave radio propagation, see
and the ARRL Technical Information
Service web page at, For
an explanation of numbers used in this bulletin, see
. Information and
tutorials on propagation can be found at, .
Also, check this:
https://bit.ly/3Rc8Njt
“Understanding Solar Indices” from September 2002 QST.