447
FXXX12 KWNP 071231
DAYDIS

:Product: Forecast Discussion
:Issued: 2026 Sep 07 1230 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
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#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity continued at low levels. The largest flare of the period
was a long-duration C2.1/Sf from Region 4524 (N12E19, Cao/beta) at
07/0901 UTC. Despite some coronal dimming in GOES SUVI imagery, no
obvious CME was detected in available coronagraph imagery. This region
showed separation in its leader spots, with overall decay observed.
Region 4528 (S11E57, Hsx/alpha) produced a C1.1 flare at 06/1334 UTC,
but was otherwise quiet and unremarkable. The remaining numbered regions
on the disk were quiet and mostly unchanged.

A large, fast moving CME was first observed in GOES CCOR1 imagery
departing the East limb at approximately 07/0200 UTC. Analysis of SUVI
and SDO imagery determined this to be a far-sided event with no impacts
likely at Earth.

Several additional CMEs were observed over the past 24-36 hours.
Modeling suggests a possible combined arrival for these eruptions on
early 08 Sep into 09 Sep.

.Forecast...
Solar activity is likely to be at low levels due to occasional C-class
flare activity, with a slight chance for M-class flares
(R1-R2/Minor-Moderate) through 09 Sep.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux reached high levels at 06/1805 UTC.
The greater than 10 MeV proton flux was still slightly elevated, but has
returned to near background levels.

.Forecast...
The greater than 2 MeV electron flux is expected to be at normal to
moderate levels, with high levels likely on 07-09 Sep. The greater than
10 MeV proton flux is expected to continue decreasing towards background
levels over the remainder of 07 Sep. Levels could increase back up to
equal or exceed threshold levels on 08-09 Sep if the anticipated CMEs
impact Earth as forecast.

Solar Wind

.24 hr Summary...
Solar wind parameters were largely at nominal levels the first half of
the period. Total field averaged near 6 nT, the Bz component fluctuated
between +/-6 nT, and solar wind speeds averaged around 350 km/s. The
exception was the IMF beginning at roughly 06/2040 UTC. Around this
time, a coherent magnetic structure began rotating through the
near-Earth environment, with Bt reaching a max of 11 nT and Bz turning
mostly northward. However, little to no magnetic response was observed.
Phi was predominantly oriented in a negative position through most of
the period.

Subsequently, at around 07/0600 UTC, Phi rotated into a positive
orientation, total field dropped to 1 nT, and Bz began to move
southward. By 07/0645 UTC, total field had rebounded to 12 nT, Bz
deviated to -9 nT, Phi was positive, and there was a slight uptick in
temp, density, and winds. Total field eventually reached a peak of 18
nT, Bz decreased to -14 nT, and wind speeds peaked at 434 km/s. This was
likely the CIR transitioning into the CH HSS.

.Forecast...
Solar wind enhancements, due to a solar sector boundary crossing
(SSBC) combined with influence from a filament CME that left the Sun on
02 Sep, are anticipated to continue through 07 Sep. Further enhancements
are likely on 08 Sep into 09 Sep with the anticipated arrival of the
multitude of CMEs from the past couple of days, combined with the onset
of the CH HSS.

Geospace

.24 hr Summary...
The geomagnetic field was quiet to unsettled, with an isolated active
period.

.Forecast...
The geomagnetic field is expected to be quiet to unsettled, with
periodic active levels on 07 Sep due to aforementioned SSBC/CME effects.
Unsettled to active levels are then expected on 08-09 Sep, with isolated
G1 (Minor) periods likely and a slight chance of reaching G2 (Moderate)
levels if the CMEs mentioned previously impact Earth as forecast.
Confidence is low on the timing and magnitude of the CME arrivals.