:Product: Forecast Discussion
:Issued: 2026 Sep 22 1230 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity

.24 hr Summary...
Solar activity continued at low levels, with the largest event being a
C2.0 flare at 22/0451 UTC from Region 4536 (N02W08, Csi/beta). There are
seven numbered sunspot regions on the visible disk: Region 4533 (S13E44,
Hsx/alpha) is a generally stable unipolar spot. Region 4534 (N11W28,
Dai/beta) underwent growth with intermediate flux emergence and pole
consolidation. Region 4535 (N12E55, Cao/beta) is decaying with trailing
spots submerging upon rotating further onto the disk. Regions 4536, 4537
(N08W19, Bxo/beta) and 4538 (N12W16, Bxo/beta) grew slightly with flux
emergence and consolidation. Region 4539 (S09E34, Dro/beta) rapidly
emerged and was numbered this period.

No Earth-directed CMEs were observed in available coronagraph imagery.

.Forecast...
Solar activity is likely continue at low levels with isolated to
occasional C-class flare activity, along with a slight chance for R1-R2
(Minor-Moderate) M-class flare events, through 24 Sep.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at normal to moderate levels.
The greater than 10 MeV proton flux remained steady at background
levels.

.Forecast...
The greater than 2 MeV electron flux is expected to continue at normal
to moderate levels through 23 Sep, with a chance for a return to high
levels by late 24 Sep. The greater than 10 MeV proton flux is expected
to persist at background levels through 24 Sep.

Solar Wind

.24 hr Summary...
Solar wind parameters reflected a ambient, slow-wind regime. Total
magnetic field strength (Bt) held steady below 4.8 nT, while the
North-South (Bz) component fluctuated mildly within a range of -3 to +4
nT. Solar wind speeds steadily drifted downward from near 330 km/s to
around 310-325 km/s late in the period. The phi angle remained in a
negative (towards the Sun) orientation.

.Forecast...
Ambient solar wind conditions will prevail through most of 22 Sep. A
disturbed solar wind environment is expected to begin late on 23 Sep
with a sector boundary crossing, followed by positive polarity coronal
hole high-speed stream (+CH HSS) influences continuing through 24 Sep.

Geospace

.24 hr Summary...
The geomagnetic field was quiet throughout the reporting period.

.Forecast...
Mostly quiet geomagnetic field conditions are expected through early 23
Sep. Unsettled to active levels are expected late on 23 Sep under early
+CH HSS effects. Isolated periods of G1 (Minor) geomagnetic storming is
likely on 24 Sep as +CH HSS influences strengthen.