Solar activity reached moderate levels early this week. The
strongest event was an M1.4 flare observed on February 11 in Region
4366. This region also produced nine C-class flares.
Region 4373 produced a C1.8/Sf flare on February 11. This region
displayed some minor area growth. Regions 4369 and 4371 exhibited
some minor decay. The other spotted regions remained unchanged. New
Region 4375 was numbered. A small loop structure near S22W80 erupted
around February 10.
Around the same time, a large filament (located near N15W25) lifted
off and disappeared from GONG H-alpha imagery. Between faint
features in disk imagery and a data gap in STEREO coronagraph
imagery, it is difficult to determine whether the filament is
superimposed over the earlier eruption or largely fell back down to
the Sun. Analysis of the coronagraph structure indicates there is no
Earth-directed component. However, there is the potential for
interaction between the eruption and the co-rotating interaction
region (CIR) ahead of an anticipated high-speed stream, which may
cause the CIR to become compressed and arrive later than under
ambient conditions.
Solar activity is expected to be at low levels through February 14.
Probability for M-class (R1-R2) flares dropped to a slight chance on
February 14, with a slight chance for X-class (R3 or greater) flares
on February 12 as Region 4366 continues to rotate behind the western
limb.
Solar wind parameters continued to reflect waning influence of a
negative polarity coronal hole high-speed stream (CH HSS) with
discrete mild disturbances likely associated with embedded transient
structures. Solar wind speeds remained generally elevated, slowly
decreasing from approximately 500 km/s to 400 km/s by the end of the
reporting period.
On February 14, the wind environment is expected to become more
enhanced late in the day due to CIR effects from a large positive
polarity coronal hole high speed stream (CH HSS) coupled with
possible weak CME effects from the February 11 eruption.
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s
Ionosphere, February 12, 2026, by F. K. Janda, OK1HH:
“The last largest sunspot group, also known as NOAA active region
4366, which suddenly appeared in the southeast of the solar disk on
January 30, has now disappeared. Until then, it was the source of a
long series of energetically significant flares. (This group could
reappear on the eastern limb of solar disk around February 23.)
Overall solar activity declined, slowly at first, and more
significantly after the setting of AR 4366.
“The geomagnetic field was mostly quiet to unsettled, with the
exception of a disturbance on February 5 and calm days on February
8-9. Due to the absence of major and longer geomagnetic disturbances
and despite the decline in solar radiation, ionospheric propagation
conditions for short waves were mostly slightly above average.
“A slight increase in solar activity can be expected from
mid-February, meanwhile it appears that geomagnetic activity could
also increase slightly at around the same time. Until then,
ionospheric propagation conditions for short waves are likely to
remain slightly above average.
“It is not yet possible to predict whether the minor disturbances
from January 16 to 17 and, in particular, the more significant
disturbances around January 20 will recur (in the latter case, this
would be around February 16, when geomagnetic activity is likely to
increase, but probably only to an ‘active’ level).”
The latest solar report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube at, .
Predicted Planetary A Index for February 14 to 20 is 5, 5, 15, 15,
15, 15, and 15, with a mean of 12.1. Predicated Planetary K Index
is 2, 2, 4, 4, 4, 4, and 4, with a mean of 3.4. 10.7-centimeter
flux is 140, 150, 160, 170, 180, 175, and 170, with a mean of 163.6.
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.
NNNN
/EX