From Newsgroup: rec.radio.amateur.space

:Product: Weekly Highlights and Forecasts
:Issued: 2025 Dec 15 0446 UTC
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# Weekly Highlights and Forecasts
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Highlights of Solar and Geomagnetic Activity
08 - 14 December 2025

Solar activity reached high levels this week, with a single X-flare
and multiple (16) M-flares. Region 4298 (S16, L=305, class/area
Cso/60 on 10 Dec) produced the only X-flare of the period: an
X1.1/2b flare at 08/0501 UTC. Other notable activity included
multiple M-class flares from several different regions. Region 4294
(S15, L=284, class/area Ekc/1180 on 08 Dec) was responsible for the
majority of the M-flares, including: an M2.2/1n at 08/0036 UTC, an
M1.0/Sf at 08/1305 UTC, an M3.1/Sf at 08/2117 UTC, an M1.1 at
09/0138 UTC, an M1.0/Sf at 09/0729 UTC, an M1.3/Sf at 090739 UTC, an
M1.6/Sf at 09/0747 UTC, an M1.5/Sf at 091514 UTC, an M1.2/Sf at
10/0422 UTC, an M1.9/Sf at 10/0737 UTC, an M1.0/1f at 10/0955 UTC,
an M1.6/Sf at 10/1343 UTC, an M4.4/2b at 10/2208 UTC, and an M1.1 at
12/0544 UTC. Region 4296 (S14, L=272, class/area Ekc/500 on 08 Dec)
contributed two M-flares: an M1.5/Sf at 09/2327 UTC, and an M2.0 at
12/0505 UTC. Region 4299 (N22, L=267, class/area Dai/130 on 08 Dec)
added three M-flares: an M2.4/2n at 08/0012 UTC, an M1.2/Sn at
08/2228 UTC, and an M2.0 at 09/0058 UTC. Finally, Region 4304 (N26,
L=252, class/area Cai/110 on 11 Dec) produced a single M-flare: an
M1.8/1n at 08/0654 UTC.



Multiple radio events accompanied some of the flares, with a total
of eight Type II and three Type IV radio sweeps, as well as a 10cm
radio burst. These included: a Type II (est 317 km/s) associated
with the M2.4/2n at 08/0012 UTC, a Type II (est 347 km/s) associated
with the X1.1/2b at 08/0036 UTC, a Type II (est 1825 km/s) and Type
IV associated with the M1.1 at 09/0138 UTC, a Type II (est 759 km/s)
thought to be associated with a far sided flare event, a Type II
(est 1053 km/s) associated with the M1.6/Sf at 10/1343 UTC, a Type
II (est 849 km/s) and 10cm burst (168 sfu) associated with the
M4.4/2b at 10/2208 UTC, a Type II (est 410 km/s) and Type IV
associated with the M2.0 at 12/0505 UTC, and a Type IV associated
with the M1.1 at 12/0544 UTC.



Several CMEs were analyzed throughout the period, with only a couple
thought to have an Earth-directed component. The most notable event
was from the X1.1/2b flare that had a westerly trajectory with an
analyzed glancing arrival at Earth late on 10 Dec to early on 11
Dec. There is a possibility this CME contributed to the G2 (Mod)
geomagnetic storming event on 10-11 Dec. There was also a CME from
the M4.4/2b flare from Region 4294 at 10/2208 UTC, but the resulting
analysis indicated the bulk of the ejecta would pass ahead of Earth.
However, it is possible more of the ejecta could have passed near
enough to Earth on 13 Dec, combined with CH HSS effects, and
enhanced conditions to the G1 (Minor) storm levels. The majority of
the other CMEs were deemed to not have Earth-directed components.



The greater than 10 MeV proton flux was at background levels
throughout the period.



The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels on 08-09 Dec, and at normal to moderate levels on 10-14
Dec.



Geomagnetic field activity was at quiet to unsettled levels on 08,
09, and most of 10 Dec, as well as 14 Dec. G2 (Moderate) storm
levels were observed the last period of 10 Dec and the first
synoptic period on 11 Dec following the arrival of a CME that likely
left the Sun on 08 Dec. Active to G1 (Minor) storming was observed
on 12 and 13 Dec in response to negative polarity CH HSS influence
mixed with possible transient effects.

Forecast of Solar and Geomagnetic Activity
15 December - 10 January 2026

M-class flares (R1-R2/Minor-Moderate) are likely, with a chance for
X-class (R3/Strong) flares through the outlook period. Chances could
increase if new, more magnetically complex regions develop or return
during the period.



Barring significant development of new active regions, the greater
than 10 MeV proton flux is expected to remain below the 10 pfu
(S1-Minor) levels throughout the outlook period.



The greater than 2 MeV electron flux is expected to reach high
levels on 16-19 Dec, 25-29 Dec, and 01-06 Jan. Normal to moderate
levels expected to prevail on 15, 20-24, 30-31 Dec, and 07-10 Jan.



Geomagnetic field activity is likely to reach G1 (Minor) storm
levels on 18 Dec, 30-31 Dec, and possibly 09 Jan, due to negative
polarity CH HSS influences. G1 levels are also likely on 22-26 Dec,
due to positive polarity CH HSS influences. Unsettled to active
levels are likely on 15-17, 19-20 Dec, 01-03 Jan, and 08-10 Jan
under the influence of negative polarity CH HSS, and on 27-29 Dec
under positive polarity CH HSS influence. Mostly quiet conditions
are expected on 21 Dec and 04-08 Jan.

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