There were two nights of visible aurora throughout the continental
US and dead HF bands due to a severe geomagnetic storm caused by
what Space.com calls "a colossal X5.1 class solar flare" and
associated coronal mass ejection (CME) on Tuesday, November 11.

Spaceweather.com for November 14 reports that a NASA model of the
latest CME suggests that it could deliver a glancing blow to our
planet's magnetic field late on November 16.
 
Meanwhile, Region 4274 was responsible for multiple low- to
mid-level C-class flares. The largest was a C4.5/Sf on November 12.
Slight decay was observed in Region 4274. Motion along the inversion
lines was minimal within the group. The rest of the spot groups were
either stable or in decay. No Earth-directed CMEs were observed.
 
Solar activity is now forecast to be high, with R1-R2
(Minor-Moderate) expected and X-class (R3-strong) activity likely on
November 15, mostly due to the flare potential of Region 4274.
 
Solar wind parameters continued to reflect persistent negative
polarity coronal hole high speed stream influences (CH HSS).  Solar
wind speeds were between 450 km/s and 600 km/s. Phi was variable
through the first half of the period before turning mostly negative
for the second half. The solar wind environment had likely become
mildly enhanced with CME influences on November 10 as the November 7
CME passed in close proximity to Earth. Stronger solar wind
disturbances were likely over November 11-12 due to the anticipated
arrival of the November 9 asymmetric halo CME.

R1-R2 (Minor-Moderate) radio blackouts are likely, with a chance for
an isolated R3 (Strong) event, through 16 November primarily due to
AR4274s past flare history coupled with its current potential.

The geomagnetic field is expected to be quiet to unsettled levels on
November 15.

Weekly Commentary on the Sun, the Magnetosphere, and the Earth's
Ionosphere, November 13, 2025, by F. K. Janda, OK1HH:

"In October, during the last solar rotation, two active regions on
the Sun: AR4246 and AR4248 were very interesting. Although they were
not the largest, their magnetic configuration indicated a possible
further increase in eruptive activity. This was confirmed during the
following parade on the far side of the Sun, when we could observe
several more powerful CMEs, especially on the eastern limb of the
solar disk.

"After their emergence on the disk, the culprit was reliably
identified as the AR4246 region, now AR4274, which continued to grow
to three times its October size. Above all, on November 9, 10, and
11, it produced a series of three large solar flares, each of which
was significantly more powerful than the previous one, including an
increase in the energy of the ejected protons by one order of
magnitude.

"The particle cloud from the second flare was faster than the one
from the first. It caught up with and cannibalized it, reaching
Earth after midnight UT on November 12 and causing powerful
geomagnetic disturbances accompanied by auroras visible at
mid-latitudes. It had the greatest impact on the ionosphere on
November 12, when MUF values dropped and attenuation increased.
After that, however, shortwave propagation conditions behaved very
unusually and interestingly.

"A sporadic-E layer appeared, ionospheric waveguides were formed,
allowing communication with very low transmitter power,
trans-equatorial routes opened up excellently, and, conversely,
routes leading through the auroral oval closed. The propagation of
radio waves through the polar region was further complicated by
attenuation in the polar cap (PCA).

"Until the AR4274 region fades away in a few days, we can expect
more similar surprises, although probably not as powerful. Solar
activity will begin to decline in the coming days, with geomagnetic
activity likely to decline a little later."

The latest report from Dr. Tamitha Skov, WX6SWW, can be found on
YouTube at, https://www.youtube.com/watch?v=RMSpOSTrcS4 .

The Predicted Planetary A Index for November 15 to 21 is 5, 10, 10,
5, 5, 12, and 10, with a mean of 8.1.  Predicted Planetary K index
is 2, 3, 3, 2, 2, 4, and 3, with a mean of 2.7.  Predicted
10.7-centimeter flux is 170, 165, 170, 165, 160, 155, and 155, with
a mean of 162.9.

For more information concerning shortwave radio propagation, see
http://www.arrl.org/propagation and the ARRL Technical Information
Service web page at, http://arrl.org/propagation-of-rf-signals. For
an explanation of numbers used in this bulletin, see
http://arrl.org/the-sun-the-earth-the-ionosphere . Information and
tutorials on propagation can be found at, http://k9la.us/ .

Also, check this:

https://bit.ly/3Rc8Njt

"Understanding Solar Indices" from September 2002 QST.