\n<\/p>\n
Solar activity has reached high levels due to a pair of X-class
flares.
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The first was an X1.8 on November 4 from Region 4274. Associated
with the flare were Type IV radio sweeps, 160 sfu Tenflare, and a
partial halo coronal mass ejection (CME) directed mostly off the NE
limb in coronagraph imagery. Although the majority of the ejecta is
expected to pass behind Earth, there is the possibility of a shock
enhancement late on November 6 to early on November 7. Region 4274
continued to be in a growth phase; however, the intermediate spots
appeared to begin to separate from the larger trailing spots.
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An X1.1 flare was also observed on November 4 from a region just
beyond E limb near S15. Associated with this flare were a Type IV
radio sweep and a non-Earth directed CME observed off the SE limb on
November 4.
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Solar wind parameters were mildly enhanced, but in decline. Solar
wind speed decreased from approximately 480 km\/s to nearly 420 km\/s. <\/p>\n
Solar activity is expected to be at moderate levels on November 3 to
17 to the delayed return of Regions 4246 and 4248, that seem to be
rotating into the Earthside solar disk between November 3 to 4. At
least two other regions are expected to emerge from the East limb
until November 10, as observed at GONG farside images.<\/p>\n
G1 storm is likely on November 7 to 8 due to reccurrence of CH HSS
influences. R1\/R2 radio blackouts are possible during the November 3
to 9 period due to the returning Regions 4246 and 4248. <\/p>\n
Weekly Commentary on the Sun, the Magnetosphere, and the Earth’s
Ionosphere, November 6, 2025, by F. K. Janda, OK1HH:<\/p>\n
The minimum activity of the Sun during its last rotation was recorded
at the end of October. The solar radio flux fell from 162 s.f.u.,
measured on October 15, to 115 s.f.u. on November 1. During the same
period, the number of sunspot groups on the solar disk decreased from
ten to two. However, coronal mass ejections, observed mainly near the
eastern limb of the solar disk, indicated that the level of activity
would soon increase rapidly.<\/p>\n
The solar flux then began to rise quickly, reaching 159 s.f.u. on
November 4. Energetically significant flares were produced mainly by
active region No. 4274, while the Earth’s atmosphere was hit by
protons with energies up to 10 MeV. The significantly intensified
solar wind was caused by the extensive coronal hole No. 94, which
passes through the central meridian at the same time. The onset of
the expected intense geomagnetic disturbance was predicted for
November 6, but it began a day earlier. On the evening of November 5,
it reached grade G3, with three-day indices up to K=6, while
continued until the forenoon hours of UTC the following day. The
effect on the ionosphere was very strong; from the beginning of the
disturbance, MUF values dropped significantly and remained very low
even on November 6.<\/p>\n
It appears that active region No. 4274 has enough energy in reserve
to continue its eruptive activity in the coming days. As the coronal
hole No. 94 shows no signs of shrinking, we can expect not only a
further increase in solar activity in the first half of November, but
also several geomagnetic disturbances. The effects on the Earth’s
ionosphere will be highly probable. Although MUF values will often
increase at the onset of disturbances, this will be followed by a
decrease accompanied by increased attenuation. This will very often
be accompanied by the scattering of radio waves on ionospheric
inhomogeneities.<\/p>\n
The latest video report from Dr. Tamitha Skov, WX6SWW, can be found
on YouTube.<\/p>\n
The Predicted Planetary A Index for November 8 to 14 is 25, 18, 12,
10, 5, 5, 5 with a mean of 11.4. Predicted Planetary K Index is 5, 4,
4, 3, 2, 2, 2 with a mean of 3.1. 10.7 centimeter flux 135, 135, 132,
140, 140, 145, 145 with a mean of 138.8.<\/p>\n
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, .<\/p>\n
Also, check this:<\/p>\n
https:\/\/bit.ly\/3Rc8Njt<\/p>\n
“Understanding Solar Indices” from September 2002 QST.
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