Monday, October 07, 2013

Weekly Propagation Forecast Bulletin



Product: Weekly Highlights and Forecasts
:Issued: 2013 Oct 07 1010 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 30 September - 06 October 2013

Solar activity was at low levels all week. The largest flare was a C2 from Region 1856 (N08, L=226, class/area=Dso/80 on 04 October) at 04/0322 UTC. Region 1857 (S08, L=228, class/area=Hsx/110 on 05 October) produced a C1 flare at 03/2023 UTC. These were the only two regions with C-class activity attributed to them. A long duration C1 flare was observed just beyond the northwest limb at approximately 02/1954 UTC and was associated witha coronal mass ejection (CME).
Another CME was associated with a filament eruption near S13E47 at about 02/2300 UTC. This second CME wsa judged to be potentially geoeffective near its periphery, but a significant disturbance was not expected. A Type-II radio sweep was observed later in the week at 05/0652 UTC. It was attributed to the eruption of a large CME visible in SOHO/LASCO coronagraph imagery beginning around 05/0735
UTC emerging frm beyond the east limb. Finally on 6 October at 1424 UTC, a C1 flare was observed in a filament channel in the southwest quadrant. Coronal dimming was observed in SDO/AIA 193 imagery beginning around 1357 UTC and lasting for a few hours while SOHO/LASCO imagery showed an asymmetrical halo CME associated with this event. Initial WSA-ENLIL model output indicates that this CME is to arrive at Earth between 2200 UTC on 09 October and 0300 UTC on 10 October. 

The 10 MeV proton flux at geosynchronous orbit reached event levles (S2) during the week in response to the filament eruption and subsequent CME on 29 September. The proton event began when the 10 pfu threshold was crossed at 30/0505 UTC. The event peaked at 30/2005 UTC when the flux reached 182 pfu, followed by a slow
decline. The event ended at 02/0510 UTC. 

The greater than 2 MeV electron flux at geosynchronous orbit remained at low to moderate levels all week. 

Geomagnetic field activity ranged from quiet to major, and possibly severe, storm levels. The CME spawned by a 35 degree filament eruption from N15W40 on 19/2337 UTC arrived on 02/0120 UTC. Solar wind speed at the ACE spacecraft jumped from near 400 km/s to approximately 636 km/s. Bt, which had been hovering near 5 nT rose to almost 32 nt over the next three hours. Bz plunged to almost -30 nT by 02/0425 UTC. The arrival of the CME was also reflected by jumps in temperature and density at ACE. The arrival at Earth's geomagnetic field quickly  followed. A 72 nT sudden impulse was observed at the Boulder magnetometer just 38 minutes (02/0158 UTC) after the shock passed the ACE spacecraft. By 0200 UTC, the estimated planetary K-index (Kp) had reached 5, indicating minor storm levels. (G1, minor, on NOAA scales) Over the course of the next four hours, conditions would reach major storm levels, Kp=6. (G2, Moderate, on the NOAA scales) The high-latitude College, Alaska observatory reported severe storm levels (K=8). Aurora was visible throughout the nighttime sector as far south as Northern Colorado and Southern Wisconsin. Preliminary estimates from GFZ Potsdam suggest the planetary K index reached 7+. The disturbed conditions, ranging from unsettled to minor storm levels, persisted through the first synoptic period of October 3rd (00-03 UTC). The days preceding the CME and following the CME were characterized by extremely quiet conditions. 

Forecast of Solar and Geomagnetic Activity 07 October - 02 November 2013

Solar activity is expected to be at low levels with a slight chance for moderate activty throughout the forecast period. 

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at normal to moderate levels for most of the period. High levels are expected 11-14 October in response to a large recurrent coronal hole high speed stream. 

Geomagnetic field activity is expected to be at unsettled levels on 09 and unsettled to active levels on 10 October with arrival of the 06 October coronal mass ejection (CME). Recurrent coronal hole high speed streams are expected to bring unsettled to active levels on 11 - 16 and 21 October. Predominately quiet conditions are expected for the remainder of the period, barring any further transient activity. 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2013 Oct 07 1010 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 2013-10-07
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2013 Oct 07     105           5          2
2013 Oct 08     105           5          2
2013 Oct 09     100           8          3
2013 Oct 10     100          12          4
2013 Oct 11     105          10          4
2013 Oct 12     105          10          3
2013 Oct 13     105           8          3
2013 Oct 14     105           8          3
2013 Oct 15     105           8          3
2013 Oct 16     105           8          3
2013 Oct 17     105           5          2
2013 Oct 18     105           5          2
2013 Oct 19     105           5          2
2013 Oct 20     100           5          2
2013 Oct 21     105          10          3
2013 Oct 22     105           5          2
2013 Oct 23     105           5          2
2013 Oct 24     100           5          2
2013 Oct 25     100           5          2
2013 Oct 26     100           5          2
2013 Oct 27     100           5          2
2013 Oct 28     100           5          2
2013 Oct 29     100           5          2
2013 Oct 30     105           5          2
2013 Oct 31     105           5          2
2013 Nov 01     100           5          2
2013 Nov 02     100           5          2
(NOAA)