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Monday, December 16, 2013

Weekly Propagation Forecast Bulletins


Product: Weekly Highlights and Forecasts
:Issued: 2013 Dec 16 0846 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact www.swpc.noaa.gov/weekly.html
#
#                Weekly Highlights and Forecasts
#
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. 

Forecast of Solar and Geomagnetic Activity 16 December - 11 January 2014

Solar activity is expected to be at low levels with a chance for M-class evens (R1 - minor - radio blackouts) through the period, particularly with the return of Old Region 1913 on 18 Dec. 

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to begin the period at high levels through 18 Dec, decreasing to normal to moderate levels for the remainder of the forecast period. 

Geomagnetic field activity is expected to reach active levels on 26-27 Dec, 03-04 Jan, and 10 Jan in response to recurrent coronal hole high speed streams. Minor storm conditions may be possible on 04 Jan. Quiet to unsettled levels are expected for the remainder of the forecast period in the absence of any transient features. 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2013 Dec 16 0846 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact www.swpc.noaa.gov/wwire.html 
#
#      27-day Space Weather Outlook Table
#                Issued 2013-12-16
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2013 Dec 16     150           5          2
2013 Dec 17     150           5          2
2013 Dec 18     155           5          2
2013 Dec 19     155           5          2
2013 Dec 20     150           5          2
2013 Dec 21     140           5          2
2013 Dec 22     135           5          2
2013 Dec 23     135           5          2
2013 Dec 24     150           5          2
2013 Dec 25     155           5          2
2013 Dec 26     155          12          4
2013 Dec 27     160          10          4
2013 Dec 28     160           8          3
2013 Dec 29     165           5          2
2013 Dec 30     165           5          2
2013 Dec 31     165           5          2
2014 Jan 01     170           5          2
2014 Jan 02     170           5          2
2014 Jan 03     175          10          4
2014 Jan 04     175          20          5
2014 Jan 05     175           5          2
2014 Jan 06     175           5          2
2014 Jan 07     170           5          2
2014 Jan 08     165           5          2
2014 Jan 09     165           5          2
2014 Jan 10     165          15          4
2014 Jan 11     160           7          2
(NOAA)