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004
FXXX12 KWNP 210031
DAYDIS

:Product: Forecast Discussion
:Issued: 2017 Oct 21 0030 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
# http://www.swpc.noaa.gov/wwire.html
#
#             Forecast Discussion
#
Solar Activity

.24 hr Summary...
Solar activity was at moderate levels today due to an M1 flare at
20/2328 UTC observed off the SE limb in the vicinity of old Region 2682
(S11, L=127). No Earth-directed CMEs were observed in coronagraph
imagery.

.Forecast...
Solar activity is expected to be at at very low levels with a chance for
C-class flares and a slight chance for M-class flares over the next
three days (21-23 Oct) due to the return of old Regions 2682 and 2683
(N13, L=111).

Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux reached moderate levels with a peak
flux of 851 pfu observed at 20/1700 UTC. The greater than 10 MeV
proton flux remained at background values.

.Forecast...
The greater than 2 MeV electron flux is expected to be at normal to
moderate levels for the next three days (21-23 Oct). The greater than 10
MeV proton flux is expected to remain at background levels all three
days of the forecast period.

Solar Wind

.24 hr Summary...
Solar wind parameters, as measured by the DSCOVR spacecraft, suggested a
weak enhancement from a positive polarity CH HSS through about 20/1330
UTC. Solar wind speeds were steady at about 450 km/s through 20/1330 UTC
when a noticeable decrease was observed. The period ended with wind
speeds hovering near 365 km/s. During the period, total magnetic field
strength ranged between 2-5 nT while the Bz component varied between +3
to -4 nT. The phi angle was oriented in a predominately positive sector.

.Forecast...
Solar wind parameters are expected to remain at near background levels
through the majority of day one (21 Oct) until the onset of a negative
polarity CH HSS is anticipated late in the day. Enhancements from the
negative polarity CH HSS are likely to continue through day two (22
Oct). By day three (23 Oct), a slow return to background levels is
expected as CH HSS effects wane.

Geospace

.24 hr Summary...
The geomagnetic field was at predominately quiet levels with an isolated
active interval observed early in the period.

.Forecast...
Mostly quiet levels are expected through a majority of day one (21 Oct).
By late on 21 Oct through early on day two (22 Oct), a chance for
unsettled to active levels are possible due to the onset of a recurrent,
negative polarity CH HSS. Mostly quiet conditions are likely from late
on 22 Oct through day three (23 Oct) as CH HSS effects wane.