:Product: Forecast Discussion
:Issued: 2026 Sep 17 0030 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity

.24 hr Summary...
Solar activity continued at very low levels with occasional B-class
flaring from an unnumbered plage region in the east. There are two
numbered sunspot regions on the visible disk that are both stable
unipolar groups.

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

.Forecast...
Solar activity is expected to remain at very low levels, with a chance
for isolated C-class flares through 19 Sep.

Energetic Particle

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

.Forecast...
The greater than 2 MeV electron flux is expected to reach high levels
through 19 Sep. The greater than 10 MeV proton flux is anticipated to
remain at background levels through 19 Sep.

Solar Wind

.24 hr Summary...
Solar wind parameters were enhanced early and decreased steadily through
the period. Total field started near 14 nT and slowly decreased to 5 nT.
Bz was mostly benign values. Solar wind speed was steady near 530 km/s.
Phi was mostly negative but had a two brief deflections in the positive
sector.

.Forecast...
Negative polarity CH HSS effects are anticipated to persist through 18
Sep. Additional enhancements are likely on 16 and 17 Sep due to flanking
influences from CMEs that departed the Sun on 13 and 14 Sep.

Geospace

.24 hr Summary...
The geomagnetic field was at quiet to active levels.

.Forecast...
Geomagnetic activity is expected to reach active to G1 (Minor) storm
levels on 16 and 17 Sep due to combined CH and CME influences. Unsettled
to active conditions are likely on 18-19 Sep as enhancements wane.