Routine Space Environment Product Issued Weekly
Issued by NWS
FXXX06 KWNP 160856
:Product: 7-day Space Weather Highlights
:Issued: 2013 Dec 16 0846 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
09 - 15 December 2013
Solar activity remained at low levels during the week, but two
Earth-directed coronal mass ejections (CMEs) were observed
associated with two filament eruptions. The first was a 15 degree
filament, centered near S31W41, that was observed in SDO/AIA 304
imagery lifting off the solar disk from 12/0304 UTC to 12/0330 UTC.
In H-alpha imagery, it appeared that the eruption was connected to
Region 1912 (S21, L=140, class/area=Hsx/110 on 09 Dec) and was
largely responsible for the C4/Sf flare at 12/0336 UTC. The eruptive
filament structure had an associated Type II (estimated at 511 km/s)
and Type IV radio sweeps as well as a partial halo CME first
observed in SOHO/LASCO C2 imagery at 12/0336 UTC.
Later on 12 December, a 7-degree filament eruption centered near
S32E27 was observed from approximately 12/0451 UTC to 12/0624 UTC.
The filament eruption appeared in conjunction with the C3 flare at
12/0659 UTC from Region 1917 (S15, L=77, class/area=Dkc/340 on 15
Dec), as observed in GOES-15 SXI imagery. An associated CME was
observed in SOHO/LASCO C2 imagery beginning at 12/0636 UTC.
WSA/Enlil model output indicated a glancing blow from the
combination of both CMEs was likely by early on 15 December.
Region 1921 (N07, L=43, class/area=Hkx/400 on 15 Dec) produced the
largest flare of the week, a C5/Sf at 12/2214 UTC, and was also the
largest region on the visible disk. The remainder of the week was
characterized by low level C-class events and several CMEs, none of
which appeared to be particularly Earth-directed.
No proton events meeting alert criteria were observed at
geosynchronous orbit, however an enhancement in 10 MeV flux was
observed from 14 - 15 December. The peak flux observed by GOES-13
was 1.68 pfu at 15/0005 UTC.
The greater than 2 MeV electron flux at geosynchronous orbit ranged
from normal background to moderate levels during the week.
Geomagnetic field activity began the week at quiet levels with the
exception on a single unsettled period on 10 December. By weeks end,
the geomagnetic field activity increased to active levels with minor
storm periods observed at high latitudes. A geomagnetic sudden
impulse was observed in global magnetometer data (e.g. 26 nT at
Canberra, Australia) at 12/1323 UTC following an interplanetary
shock seen in ACE/SWEPAM data at 13/1210 UTC. This shock was
believed to herald the arrival of a corotating interaction region in
advance of a negative polarity coronal hole high speed stream. Over
the next 36 hours, solar wind speed would increase from around 270
km/s to reach a maximum of 607 km/s on 14/2114 UTC. Examination of
ACE/EPAM low energy particle flux showed peaks around 14/1400 and
14/2300 UTC, suggesting the CMEs mentioned earlier arrived, embedded
in the high speed solar wind stream. Bz reached a minimum near -12
nT at 14/0248 UTC and active conditions were subsequently observed
during the 14/0300-0600 UTC synoptic period. A second active period
was observed during the 14/1800-2100 UTC synoptic period while
activity reached minor storm levels at high latitudes. The following
day saw a return to mostly quiet conditions.