:Product: Forecast Discussion
:Issued: 2021 Jun 16 1230 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
Solar Activity

.24 hr Summary...
Solar activity was very low. Region 2833 (N25E31, Hsx/alpha) remained
quiet and stable. No Earth-directed CMEs were observed in available
coronagraph imagery.

.Forecast...
Solar activity is expected to be very low on 16-18 Jun.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at normal to moderate levels,
and 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 on 16 Jun, increasing to moderate to high levels on
17-18 Jun in response to the high speed solar wind stream described
below. The greater than 10 MeV proton flux is expected to persist at
background levels in the absence of significant active regions.

Solar Wind

.24 hr Summary...
The high speed stream associated with the south polar coronal hole and
extension has established itself based on measurements at DSCOVR.  Wind
speed remained in the mid to upper 500 km/s range, temperature remained
elevated, and the Phi angle was negative.  Bt decreased from 14 nT to 4
nT over the past 24 hours and Bz relaxed from -10 nT at the beginning of
the period to hover near 0 nT by forecast time.

.Forecast...
Enhanced solar wind conditions are expected to persist through 17 Jun
before the coronal hole moves out of a geo-effective position on the
18th

Geospace

.24 hr Summary...
The geomagnetic field was quiet to active, with a single period of
G1 (Minor) storm conditions in response to the high speed stream
described above.

.Forecast...
As the high speed solar wind stream becomes established, the geomagnetic
field is expected to be at unsettled to active levels, with a lingering
chance for a G1 (Minor) storm period on 16 Jun.  The threat of a minor
storm period on 17 Jun appears to be diminishing and the forecast was
adjusted accordingly.  A return to mostly quiet to unsettled conditions
is expected on 18 Jun.