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966
FXXX12 KWNP 211231
DAYDIS

:Product: Forecast Discussion
:Issued: 2017 Sep 21 1230 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 very low with a few B-class flares observed.
NOAA/SWPC Region 2681 (S12E67, Hsx/alpha) was assigned and produced
several B-class flares. Region 2680 (N08W73, Hsx/alpha) was little
changed, but produced the largest B-class flare of the period, a B8
flare at 20/1932 UTC. No Earth-directed CMEs were observed in available
coronagraph imagery.

.Forecast...
Solar activity is expected to be very low, with a slight chance for
C-class flares all three days (21-23 Sep) due to the combined flare
potential of Regions 2681 and 2680.


Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at moderate to high levels with
a max flux of 33,761 pfu at 20/1840 UTC. The greater than 10 MeV proton
flux continued at background values.

.Forecast...
The greater than 2 MeV electron flux is expected to continue at high
levels all three days (21-23 Sep) and the greater than 10 MeV proton
flux is expected to remain at background levels.


Solar Wind

.24 hr Summary...
Solar wind parameters were indicative of waning CH HSS influences. Total
field strength ranged primarily from 3 to 5 nT, and the Bz component was
variable between +/- 4 nT. Solar wind speed decreased from 475 km/s to
start the period, down to speeds of around 420 km/s by the periods end.
The phi angle remained positive.

.Forecast...
Solar wind speed is expected to decline unsteadily towards ambient
background conditions during the forecast period (21-23 Sep).


Geospace

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

.Forecast...
The geomagnetic field is expected to be quiet to unsettled all three
days (21-23 Sep) under a nominal solar wind regime.