Product: Weekly Highlights and Forecasts
:Issued: 2013 Aug 26 0608 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 19 - 25 August 2013
Solar activity was at very low to low levels during the period. The period began at low levels which persisted through 23 August. The majority of the C-class flare events were from Regions 1818 (S07, L=214, class/area Dhc/340 on 13 August), 1820 (S12, L=177, class/area Dai/130 on 21 August), and 1828 (N16, L=089, class/area Cao/60 on 20 August). The largest flare of the period was a C4/Sf which occurred at 22/0506 UTC from Region 1820. Moderate growth was observed in Region 1820 from 19-21 August and in Regions 1830 and 1831 on 22 and 23 August, respectively. By 25 August, the majority of the spotted regions had either decayed to plage or rotated around the western limb. Solar activity was at very low levels on 24 and 25 August. A 51-degree filament eruption centered near S47E24 erupted between 20/0400 UTC and 20/0829 UTC. An associated coronal mass ejection (CME) with an approximate speed of 681 km/s, first seen in SOHO/LASCO C2 imagery beginning at 20/0824 UTC, was observed with the majority of the ejecta off the SW limb.
A small enhancement in the greater than 10 MeV proton flux at geosynchronous orbit was observed beginning at approximately 20/2300 UTC, reached a maximum of 2 pfu at 21/1330, and returned to background levels around 21/2100 UTC. The enhancement was likely associated with backsided CME activity.
The greater than 2 MeV electron flux at geosynchronous orbit was at moderate levels on 22 August. High levels were observed the rest of the period due to a combination of coronal hole high speed stream
(CH HSS) and CME effects.
Geomagnetic field activity ranged from quiet to active levels. The period began with mostly quiet conditions on 19 and 20 August. By late on 20 August, the total field component (Bt) increased from 4 nT to 11 nT while the Bz component went south to -10 nT. A corresponding increase in solar wind speed and density was observed at 20/2135 UTC indicating a weak shock arrival from the 18 Aug CME associated with an M1 flare. Subsequently, a geomagnetic sudden impulse (26 nT) was observed on the Boulder magnetometer at 20/2231 UTC. Solar wind speed continued to increase from 380 km/s to near 550 km/s from 21 to 22 August with the total field between 3 and 10 nT while the Bz component varied between +7 nT and -6 nT as a positive polarity CH HSS became geoeffective. Solar wind conditions persisted through mid-day on 23 August reaching a maximum of 610 km/s at 22/0712 UTC. The geomagnetic field responded with unsettled to active levels on 21 August while quiet to active levels were observed on 22 and 23 August. Another weak shock passage (3 nT deviation in total field) was observed at 23/2355 UTC due to the arrival of a glancing blow from the 20 August CME. No significant geomagnetic effects were observed with the shock passage. The geomagnetic field was mostly quiet on 24 and 25 August.
Forecast of Solar and Geomagnetic Activity 26 August - 21 September 2013
Solar activity is expected to be at very low to low levels. A chance for an M-class flare exists with the return of old Region 1817 (S21, L=241) from 02-15 September.
No proton events are expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be normal to moderate levels with high levels expected on 27-29 August, 02-07 September, 12-16 September, and again on 9-21 September due to activity associated with recurrent CH HSSs.
Geomagnetic field activity is expected to be mostly quiet with the exception of quiet to unsettled levels on 26-27 August and 05 September due to CH HSS activity. Unsettled to active levels are expected on 31 August - 02 September, 10-14 September, and again on 17-19 September due to recurrent CH HSS activity.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2013 Aug 26 0608 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 2013-08-26
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2013 Aug 26 110 12 3
2013 Aug 27 105 8 3
2013 Aug 28 100 5 2
2013 Aug 29 100 5 2
2013 Aug 30 95 5 2
2013 Aug 31 90 15 4
2013 Sep 01 90 15 4
2013 Sep 02 100 10 3
2013 Sep 03 105 5 2
2013 Sep 04 105 5 2
2013 Sep 05 110 8 3
2013 Sep 06 115 5 2
2013 Sep 07 120 5 2
2013 Sep 08 125 5 2
2013 Sep 09 125 5 2
2013 Sep 10 125 10 3
2013 Sep 11 125 15 4
2013 Sep 12 125 18 4
2013 Sep 13 125 8 3
2013 Sep 14 125 8 3
2013 Sep 15 120 5 2
2013 Sep 16 115 5 2
2013 Sep 17 115 12 4
2013 Sep 18 110 18 4
2013 Sep 19 105 15 4
2013 Sep 20 105 5 2
2013 Sep 21 105 5 2
(NOAA)
