Routine Space Environment Product (Daily)
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FXXX12 KWNP 201231

:Product: Forecast Discussion
:Issued: 2017 Sep 20 1230 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
#             Forecast Discussion
Solar Activity

.24 hr Summary...
Solar activity was very low with only low-level B-class flares observed
from an unnumbered spot group rotating onto the visible disk. Region
2680 (N08W59, Hsx/alpha) remained inactive. No Earth-directed CMEs were
observed in available coronagraph imagery.

Solar activity is expected to remain very low all three days (20-22
Sep), with a slight chance for C-class flares by day three as former
Region 2673 (S09, L=119) nears its return to the east limb.

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at high levels with a maximum
flux of 34,879 pfu at 19/1625 UTC. The greater than 10 MeV proton flux
remained at background values.

The greater than 2 MeV electron flux is expected to continue at high
levels all three days (20-22 Sep), with a chance for very high levels on
days one and two (20-21 Sep), due to CH HSS influences. The
greater than 10 MeV proton flux is expected to maintain background
levels all three days.

Solar Wind

.24 hr Summary...
Solar wind parameters remained indicative of waning CH HSS influences.
Total field was steady at 4 nT. The Bz component was variable, but at
benign values. Solar wind speed gradually declined from 525 km/s to near
475 km/s. The phi angle was positive.

Solar wind speed is anticipated to continue slowly declining towards an
ambient background regime on days one through three (20-22 Sep) as the
effects of the positive polarity, north polar CH HSS wane.


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

The geomagnetic field is expected to be primarily quiet to unsettled,
with an isolated active period still likely on day one (20 Sep) as solar
wind speeds continue to decrease, but remain elevated. Day two (21 Sep)
is expected to be at quiet to unsettled levels due to waning CH HSS
effects. A return to quiet conditions is expected on day three (22 Sep)
as the CH HSS rotates away from geoeffective position. is the U.S. government's official web portal to all federal, state and local government web resources and services.