Routine Space Environment Product Issued Weekly
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FXXX06 KWNP 290626
WEKHIL

:Product: 7-day Space Weather Highlights
:Issued: 2017 May 29 0600 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
22 - 28 May 2017

Solar activity was at very low levels to low levels over the period.
Low levels were observed on 28 May due to a C3/Sf flare at 28/1928
UTC and a C1/Sf flare at 28/2313 UTC from Region 2659 (N13, L=041,
class/area Dao/220 on 28 May). Other events included an approximate
25 degree filament eruption centered near N04W03 which was observed
lifting off in H-alpha imagery beginning at 22/1900 UTC. An
associated partial-halo CME was observed with the majority of the
ejecta off the western limb in SOHO/LASCO C2 imagery beginning at
23/0512 UTC. WSA-Enlil modelling of the event showed an
Earth-directed component with the associated CME.

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels from 22-27 May with a peak flux of 26,098 pfu observed
at 22/1650 UTC. Electron flux dropped to normal levels on 28 May due
to the arrival of the 23 May CME.

Geomagnetic field activity ranged from quiet to G3 (Strong) storm
levels over the period. The period began under the declining
influence of a negative polarity coronal hole high speed stream (CH
HSS). Solar wind speeds declined from approximately 570 km/s to near
300 km/s by 27 May while total field was between 3 nT and 7 nT.
Quiet to unsettled levels were observed on 22-23 May with quiet
levels from 24 May through most of 27 May. Beginning at 27/1447 UTC,
a small shock was observed indicating the arrival of the 23 May CME.
Total field increased from 3 nT to 10 nT while the solar wind
increased from 303 km/s to 353 km/s. Although solar wind speed
remained fairly steady between 350 km/s and 380 km/s, another
increase in total field was observed with the transition into the
magnetic cloud at 27/2000 UTC. Total field reached a maximum of 23
nT at 27/2230 UTC before it slowly declined to near 13 nT by the end
of the period. The Bz component deflected southward to -20 nT
beginning at 27/2036 UTC and remained negative until 28/1442 UTC. A
geomagnetic sudden impulse was observed at 27/1536 UTC (19 nT at the
Boulder magnetometer) indicating the arrival of the CME. The
geomagnetic field responded with a period of G2 (Moderate) storm
levels late on 27 May followed by G1-G3 (Minor-Strong) storm levels
through midday on 28 May. A decrease to quiet to active levels was
observed during the second half of 28 May.



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