<AUR>.Forecast Discussion

:Product: Forecast Discussion
:Issued: 2019 Sep 22 0030 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity

.24 hr Summary...
Solar activity was very low. The solar disk was spotless. An approximate
10 degree filament disappeared in the SW quadrant beginning at
21/0110 UTC in SDO/AIA 304 imagery; however, it appears to have been
reabsorbed. No Earth-directed CMEs were observed.

Analysis of the 20 degree filament eruption at 19/2200 UTC indicated the
possibility of a glancing blow from the narrow, slow-moving CME early on
25 Sep. Most of the ejecta was off the Sun-Earth line but the periphery
of the CME may have embedded with the HSS that is expected to be
geoeffective later this week.

.Forecast...
Solar activity is expected to be at very low levels on 22-24 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 was at background levels.

.Forecast...
The greater than 2 MeV electron flux is expected to be at normal to
moderate levels with a chance of high levels on 22-24 Sep. The greater
than 10 MeV proton flux is expected to continue at background levels.

Solar Wind

.24 hr Summary...
Solar wind parameters were at nominal levels. Solar wind speed increased
from approximately 285-370 km/s. Total field ranged from 1-7 nT while
the Bz component was between +6/-7 nT. Phi angle was predominantly in a
positive (away) solar sector with brief deflections into a negative
(towards) sector between 21/0350-0955 and 21/1545-1830 UTC.

.Forecast...
Solar wind parameters are expected to become enhanced early to midday on
23 Sep with the arrival of a negative polarity CH HSS. Activity is
expected to persist into 24 Sep. Solar wind speeds are expected to be in
the 450-550 km/s range based on STEREO A MAG & PLASTIC data.

Geospace

.24 hr Summary...
The geomagnetic field was quiet to unsettled.

.Forecast...
The geomagnetic field is expected to be mostly quiet on 22 Sep. Quiet to
unsettled conditions are expected on 23-24 Sep with isolated active
periods possible on 23 Sep due to CH HSS effects.