779
FXXX12 KWNP 310031
DAYDIS

:Product: Forecast Discussion
:Issued: 2025 Dec 31 0030 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
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#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity has been at low levels for the past 24 hours, with few
C-class flares mostly coming from Region 4325 (S08E17, Eki/beta-gamma).
The largest flare of the period was a C5.0/Sf, peaked at 30/0645 UTC,
from Region 4324 (N24E25, Dao/beta-gamma).

Region 4330 (S16E41, Axx/alpha) was responsible for two eruptions seen
in SUVI imagery. The first eruption was associated with a CME, first
observed at coronagraph imagery at 30/0700 UTC and closely followed by a
second CME from the northeast quadrant (potentially from near Region
4324). But none of their modeled trajectory indicated direct impact
near-Earth.

Further coronagraph images are necessary to evaluate if the second
eruption from Region 4330 will result in a visible CME. No other
Earth-directed CME was observed during the period.

.Forecast...
Solar activity is likely to be moderate with a chance for X-class flares
through 02 Jan due to the current magnetic complexity and development of
the active regions on the visible solar disk.


Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux, measured at geostationary orbit by
GOES-19, reached a peak level of 5,612 pfu at 30/1545 UTC and decreased
to moderate levels after 30/1915 UTC. The greater than 10 MeV proton
flux remained at background levels during the period.

.Forecast...
The greater than 2 MeV electron flux is expected to reach high levels
again on 31 Dec and 01-02 Jan. The greater than 10 MeV proton flux has a
slight chance of crossing threshold on days 31 Dec, 01-02 Jan.

Solar Wind

.24 hr Summary...
Solar wind parameters remained at background conditions during most of
the day. Solar wind speed oscillated around 400 km/s, but reached a peak
of 563 km/s at 30/1514 UTC during a brief disturbance. Total IMF
oscillated around 5 nT most of the period, and reached 9 nT at 30/2323
UTC. The maximum southward component of Bz reached -6 nT at 30/1515 UTC,
during a brief disturbance that was likely anticipating a sector
crossing observed as the phi angle change (from mostly positive to
mostly negative after that), likely associated with a negative CH HSS.

.Forecast...
Solar wind parameters are expected to increasingly respond to the
influence of a negative CH/HSS located at the northwest solar quadrant
in the next days: higher speeds, lower densities and negative phi angle.
By late 31 Dec / early 01 Jan, a glancing blow of CME that left the Sun
on 28 Dec is anticipated to disturb the solar wind near Earth. Later on
01 Jan, an extra disturbance caused by the multiple CMEs from 29 Dec is
also possible.

Geospace

.24 hr Summary...
The geomagnetic activity has been at quiet to unsettled levels for the
past 24 hours.

.Forecast...
The geomagnetic activity is expected to be at quiet to active levels on
31 Dec, unsettled to minor storm levels on 01 Jan and unsettled to
active levels on 02 Jan.