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FXXX06 KWNP 220426

:Product: 7-day Space Weather Highlights
:Issued: 2014 Dec 22 0358 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact on the Web
#                7-day Space Weather Highlights
Highlights of Solar and Geomagnetic Activity
15 - 21 December 2014

Solar activity was dominated by Regions 2242 (S28, L=238, class/area
Ekc/1080 on 19 Dec) and 2241 (S09, L=215, class/area Ekc/720 on 19
Dec). Region 2242 produced an X1/3b flare on 20 December at 0028
UTC. Associated with this event was a Type II radio sweep (est.
speed 900 km/s), a 2300 sfu Tenflare, and a coronal mass ejection
(CME) directed off the SW limb. This was the largest flare of the
week. The same region also produced an M8/2b flare on 17 December at
1901 UTC accompanied by Type II (est. speed 910 km/s) and Type IV
radio sweeps, as well as a 320 sfu Tenflare. The majority of the
ejecta from the associated CME had a southerly trajectory. However,
it had a weak Earthward component and model output suggested arrival
at Earth late on 19 December. The third largest flare of the week
was an M6/2n flare from Region 2141 on 18 December at 2158 UTC
accompanied by a Type-II radio sweep (est. speed 664 km/s) and an
asymmetric full halo CME first observed in SOHO/LASCO C3 imagery at
19/0104 UTC. WSA-Enlil model output suggested an arrival of this CME
midday on 21 December. There were six other low-level M-class flares
during the week, evenly split between Regions 2241 and 2242.

No proton events were observed at geosynchronous orbit, although the
greater than 10 MeV proton flux was enhanced on 21 December,
reaching a peak value of 3.2 pfu at 21/2015 UTC in conjunction with
the passage of the CME from 18 December.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal to moderate levels.

Geomagnetic field activity was mostly quiet to unsettled until 21
December when active conditions were recorded. The ACE satellite
observed a pair of discontinuities in the solar wind field on 21
December. The first discontinuity at 21/0235 UTC was weak and
possibly indicated the arrival of a glancing blow from the 17
December CME. Total field increased slightly from 6 nT to 8 nT while
the Bz component mostly remained southward to -8 nT for about 16
hours. No significant increase in solar wind speeds was observed as
they remained steady at about 350 km/s. At about 21/1824 UTC, the
second stronger discontinuity was observed. This second
discontinuity probably signaled the arrival of the 18 December CME.
Total field increased sharply from 9 nT to 17 nT while the Bz
component dipped further southward to -13 nT. Wind speeds increased
from approximately 350 km/s to about 450 km/s. Subsequent increases
were also observed in density and temperature. The magnetosphere
responded with active conditions. is the U.S. government's official web portal to all federal, state and local government web resources and services.