Subject: Weekly Highlights of Solar and Geomagnetic Activity, 10 - 16 November 2025

:Product: Weekly Highlights and Forecasts
:Issued: 2025 Nov 17 0337 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
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# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
10 - 16 November 2025

Solar activity ranged from low to high levels. Region 4274 (N24,
L=275, class/area Ekc/1100 on 11 Nov) was the largest and most
complex, and responsibile for the majority of the major events
during the past week. During the week, Region 4274 produced a total
of 72 C-class, 5 M-class and 3 X-class flares. Region 4276 (S17,
L=240, class/area Dai/180 on 07 Nov) produced 10 C-class flares.
Regions 4277 (S06, L=239, class/area Dai/150 on 09 Nov), 4279 (S13,
L=207, class/area Hsx/030 on 11 Nov) and 4281 (S14, L=289,
class/area on 14 Nov) all produced 1 C-class flare. Newly numbered
Region 4284 (S07, L=177, class/area Dso/060 on 16 Nov) produced
three C-class flares late in the period.

On 10 Nov, high levels (R3/Strong) were observed due to a long
duration X1.2/2B flare observed from Region 4274 at 10/0919 UTC.
Associated with this event was a Castelli U radio event, a 1,311
km/s Type II and a Type IV sweep and a 860 km/s Tenflare. Also
associated with this event was an asymmetric-halo CME with the bulk
of the ejecta off the NW limb. Modelling of the event indicated an
arrival early on 12 Nov.

High activity levels continued on 11 Nov, when Region 4274 produced
an X5.1/3B flare at 11/1004 UTC. Associated with this event was a
Castelli U radio event, a 1,350 km/s Type II sweep and a 10,000 sfu
Tenflare. An associated asymmetric-halo CME was observed with the
bulk of the ejecta having a NW bias. Modelling of the CME indicated
an arrival time of middle to late on 12 Nov. Low levels were
observed on 12-13 Nov.

High solar activity was again observed on 14 Nov following a X4.0/3b
flare from Region 4274 at 14/0830 UTC. Associated with this event
was a Castelli U radio event, a Type IV sweep and a 1,100 sfu
Tenflare. An associated CME was visible in LASCO C2 imagery off the
W limb starting at about 14/0800 UTC. Analysis and modelling of the
event indicated that the main body of the ejecta should be well
ahead of Earth. However, modelling of the halo portion indicated a
possible Earth impact late on 15 Nov to early on 16 Nov. As region
4274 exited the NW limb, it produced a parting M3.1 (R1-Minor) flare
at 16/0817 UTC.

The greater than 10 Mev at 10 pfu protons at geosynchronous orbit
exceeded S1-S3 (Minor-Strong) levels two times during the period.
The first 10 Mev event began at 10/1030 UTC, reached a peak of 1,456
pfu at 12/0215 UTC and ended at 12/2100 UTC. The second, smaller 10
pfu event began at 14/0920 UTC, reached a peak of 16.5 pfu at
14/0950 UTC and ended at 14/1325 UTC. The greater than 100 Mev at 1
pfu protons at geosynchronous orbit exceeded event threshold. The
greater than 100 Mev event began at 11/1100 UTC, reached a peak of
37 pfu at 12/0150 UTC and ended at 12/0925 UTC. All of these
particle events were associated with the previosily described
X-class flare events.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 10-13 Nov with a peak of 10,090 pfu exceeded at
11/1220 UTC. Normal to moderate levels were reached on 14-16 Nov.

Geomagnetic field activity was between quiet to G4 (Severe)
geomagnetic storm levels. Unsettled to active levels were observed
on 10-11 Nov due to enhanced HSS influence on 10 Nov into mid 11
Nov. About midday on 11 Nov, an IP shock passage was observed,
likely the arrival of the 09-10 Nov CMEs. On 12-13 Nov, solar wind
parameters reflected the onset of a CME that left the Sun on 10 Nov.
Total magnetic field strength reached a peak of 63 nT, while the Bz
component reached as far south as -55 nT. Solar wind speeds
increased to a peak of about 740 km/s late on 11 Nov. Late on 12
Nov, solar wind speeds reached peaks near 1,000 km/s. During 12 Nov,
the geomagnetic field was at G1 (Minor) to G4 (Severe) levels while
13 Nov, activity levels decreased to quiet to G3 (Strong) levels.
Quiet to unsettled levels were observed on 14-15 Nov. 16 Nov saw
unsettled to active levels due to minor enhancements from the 14 Nov
CME.

Forecast of Solar and Geomagnetic Activity
17 November - 13 December 2025

Solar activity is likely to be at R1 (Minor) levels on 12-27 Nov and
13 Dec. Levels are likely to increase to R1-R3 (Minor-Strong) levels
on 28 Nov-30 Nov and 01-12 Dec, primarily due to the flare potential
and return of old Region 4274 (N24, L=275).

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to be at high levels over 18-19, 22-23 and 27-30 Nov and
01-02 and 07-12 Dec, all due to coronal hole influence. The
remainder of the outlook period is likely to be at normal to
moderate levels.

Geomagnetic field activity is expected to range from quiet to G2
(Moderate) geomagnetic storm levels. G1 (Minor) conditions are
likely on 17 Nov due to anticipated influence both a negative
polarity CH HSS and waning remants from a CME. G2 (Moderate) levels
are likely on 26 Nov, 03 Dec and 13 Dec due to CH HSS influence.
Unsettled to active conditions are likely on 18-19, 21-22, 24-25 and
27-30 Nov and 01-02 and 04-07 Dec, all due to CH HSS influence.
Mostly quiet levels are expected on 20 and 23 Nov and 08-12 Dec.


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