Routine Space Environment Product Issued Weekly
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FXXX06 KWNP 240225
WEKHIL

:Product: 7-day Space Weather Highlights
:Issued: 2017 Apr 24 0153 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
#
#                7-day Space Weather Highlights
#
Highlights of Solar and Geomagnetic Activity
17 - 23 April 2017

Solar activity reached low levels on 17-18 Apr due to isolated
C-class flare activity from Region 2651 (N12, L=070,
class/area=Cso/150 on 23 Apr), but solar activity was at very low
levels through the remainder of the period (19-23 Apr). The largest
event of the period, a long-duration C5/Sf flare at 18/2010 UTC with
both Type-II and IV radio emissions, had an associated CME that was
observed in C2 coronagraph imagery beginning at 18/1948 UTC. CME
analysis and WSA-Enlil modelling suggested that this event did not
have an Earth-directed component, however, it is likely that this
event reached Earth late on 21 Apr. No other Earth-directed CMEs
were observed.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit reached
high levels on 17-18, 21-23 Apr, moderate levels on 20 Apr, and
normal levels on 19 Apr.

Geomagnetic field activity was quiet on 17 Apr and quiet to
unsettled on 18 Apr under a nominal solar wind regime. The influence
of a recurrent, positive polarity CH HSS caused periods of G1
(Minor) geomagnetic storm conditions on 19 Apr and G1-G2
(Minor-Moderate) storm conditions on 20 Apr. The likely arrival of a
CME (from 18 Apr) combined with the onset of a CIR caused G1 (Minor)
geomagnetic storm levels late on 21 Apr. The influence of a
recurrent, negative polarity CH HSS began early on 22 Apr and caused
G1-G2 (Minor-Moderate) geomagnetic storms on 22-23 Apr.



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