543
FXXX12 KWNP 040036
DAYDIS

:Product: Forecast Discussion
:Issued: 2025 Dec 04 0035 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity was at low levels with only C-class flares.

Region 4288 (L=47, Dai/beta) rotated off the disk early in the reporting
period, but any flares it produces will still be visible over the limb
for another day or two. Region 4294 (S15E18, Fkc/beta-gamma-delta)
remains the largest region on the disk but is appearing to be
simplifying magnetically. Region 4295 (N04E25, Cso/beta) developed a few
new spots in its southwest. Region 4296 (S14E37, Ekc/beta-gamma-delta)
continues to have flux emergency in its intermediary region, but still
no corresponding increase in flare activity. New Region 4301 (S07W44,
Cri/beta-gamma) developed rapidly above Region 4297 (S12W40, Bxo/beta)
throughout the period.

A long filament erupted from the southwest quadrant late in the UT
morning (~0900-1200 UTC). A sympathetic eruption was triggered in the
northwest at 03/1230 UTC. This second eruption was much faster than the
filament eruption and the two structures combined in coronagraph
imagery. These structures became visible in LASCO C2 coronagraph imagery
at 03/1106Z UTC (at L1) and in GOES CCOR-1 at 03/1330 UTC (at GEO).
Model analysis shows this CME passing ahead of Earths orbit and no
impact is anticipated.

.Forecast...
Isolated to occasional M-class flares are expected (75%) through 06 Dec,
with a chance for X-class flares (30%), given past flare history and the
potential of current active regions on the disk.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux in geosynchronous orbit continued
at high levels for most of the reporting period, with a peak flux of
6,340 particle flux units reached near 03/1350 UTC, before crossing
below the alert threshold at 03/1845 UTC.

The greater than 10 MeV proton flux in geosynchronous orbit remained at
background levels.

.Forecast...
The greater than 2 MeV electron flux is expected to remain at moderate
levels 04-05 Dec due to the arrival of fast solar wind associated with a
coronal hole high speed stream, returning to high levels on 06 Dec after
the HSS passage.

An enhancement to the 10 MeV proton flux in geosynchronous orbit due to
the aforementioned X1.9 event from 01 Dec cannot be ruled out as
sometimes events from the eastern limb take tens of hours to days to
reach Earth. This combined with the flare potential currently exhibited
by Earth-facing active regions will keep 10 MeV protons at a slight risk
(15%) of reaching the 10 particle flux unit threshold through 05 Dec.

Solar Wind

.24 hr Summary...
Solar wind parameters showed the arrival of the expected co-interacting
region (CIR) associated with a high speed stream, starting around
03/0800 UTC. The total interplanetary magnetic field (Bt) slowly
increased throughout the reporting period, reaching a maximum of 21 nT
at 03/2155 UTC. The magnetic field components suggest the arrival of an
embedded CME (likely from the X1.9 flare on 01 Dec) starting at 03/1250
UTC. The north-south component (Bz) ranged from -15 to 16 nT but was
largely south (negative) for the majority of the reporting period with
an average of -10 nT. The solar wind speeds have been slow to increase
but reached ~530 km/s by the end of the reporting period. Phi was
largely in a positive (away from the Sun) orientation until 03/1919 UTC,
when it crossed into the negative (towards the Sun) orientation,
indicating the full arrival of the high speed stream from the negative
polarity coronal hole.

.Forecast...
The solar wind environment is anticipated to remain more turbulent into
the early hours of 04 Dec, due to the continued passage of the entangled
CME. The environment will likely remain enhanced due to fast solar wind
conditions through 06 Dec.

Geospace

.24 hr Summary...
Geomagnetic field activity was quiet to unsettled at the beginning of
the reporting period, with minor to strong storming conditions in the
later half.

.Forecast...
The geomagnetic field will likely remain at storming levels through the
beginning of 04 Dec, with largely unsettled to active conditions likely
on 05-06 Dec as the system recovers from the CIR/CME arrival and settles
into fast solar wind conditions.