Routine Space Environment Product (Daily)
Issued by NWS

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174
FXXX12 KWNP 210031
DAYDIS

:Product: Forecast Discussion
:Issued: 2018 Feb 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 very low and the visible disk remained spotless. No
Earth-directed CMEs were observed in available coronagraph imagery.

.Forecast...
Solar activity is expected to be very low all three days (21-23 Feb).


Energetic Particle

.24 hr Summary...
The greater than 2 MeV electron flux was at high levels, with a maximum
flux of 9,120 pfu at 20/0130 UTC. The greater than 10 MeV proton flux
remained at background values.

.Forecast...
The greater than 2 MeV electron flux is expected to continue at high
levels on day one (21 Feb) and decrease to moderate to high levels on
day two (22 Feb) in response to likely effects from a CIR ahead of a CH
HSS. A return to high flux is expected on day three (23 Feb) due to CH
HSS influences. The greater than 10 MeV proton flux is expected to
continue at background levels all three days.


Solar Wind

.24 hr Summary...
Solar wind parameters were indicative of the waning influences of a
negative polarity CH HSS and a return towards a slow solar wind regime.
Total IMF strength was primarily steady from 3 to 4 nT and the Bz
component underwent only weak deviations. Solar wind speed gradually
decreased from early period values of 525 km/s to end of period speed
near 400 km/s. The phi angle was predominantly negative (towards the
Sun).

.Forecast...
The solar wind environment is expected to be primarily benign most of
day one (21 Feb), but may become mildly disturbed later in the day due
to approaching CIR influences ahead of an extension of the negative
polarity south polar CH HSS. Day two (22 Feb) is likely to experience an
enhanced IMF due to lingering CIR influences followed by increasing
solar wind speed due to CH HSS onset. WSA-Enlil ambient model runs are
currently too early with speed increase, but indicate connection with
the north flank of the CH HSS and forecast solar wind speed of 600 km/s.
Recurrence suggests a weaker connection as speed last rotation was 500
km/s. Elevated solar wind speed is anticipated to continue into day
three (23 Feb) as CH HSS influences continue, but begin to wane.


Geospace

.24 hr Summary...
The geomagnetic field was unsettled the first synoptic period of the
UTC-day, but became quiet afterwards.

.Forecast...
The geomagnetic field is expected to be quiet to unsettled on day one
(21 Feb) in response to the mildly disturbed solar wind environment. Day
two (22 Feb) is expected to be quiet to unsettled, with an isolated
active period likely in response to CIR and CH HSS influences. Day three
(23 Feb) is expected to be quiet to unsettled as CH HSS effects continue
but weaken.



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