Product: Weekly Highlights and Forecasts
:Issued: 2018 Aug 27 0539 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact http://www.swpc.noaa.gov/weekly.html
#
# Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity 20 - 26 August 2018
Solar activity was at very low levels. Regions 2719 (S07, L=131, class/area Cro/040 on 23 Aug) and 2720 (N08, L=136, class/area Dao/100 on 25 Aug) developed on the solar disk on 18 Aug and 23 Aug respectively. Both regions were responsible for several low level B-class flares. The largest was a B4 flare at 25/1048 UTC from Region 2720. Other activity included two coronal mass ejections
(CME) observed on 19 and 20 Aug. The first was a narrow CME off the SW limb at 19/0812 UTC in SOHO/LASCO C2 imagery. The CME originated from a filament eruption near S09W06 at 19/0542 UTC. The latter CME was caused by a filament eruption at approximately 20/1100 UTC from
the NW quadrant. An associated faint partial halo CME was observed off the W/SW limb at 20/2136 UTC in C2 imagery. WSA/ENLIL modelling of the events showed only weak effects from possible glancing blows late on 21 Aug and late on 24 Aug.
No proton events were observed at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit reached high levels throughout the period. The largest flux of the period was 10,300 pfu observed at 21/2150 UTC.
Geomagnetic field activity ranged from quiet to G3 (Strong) geomagnetic storm levels. The period began under the influence of a negative polarity coronal hole high speed stream (CH HSS). Solar
wind speeds were elevated to near 670 km/s with total field initially at 12 nT on 20 Aug. By 21 Aug, solar wind speed was in decline while total field was at 5 nT or less. Solar wind slowly decreased over the next few days as nominal conditions were reached by 23 Aug. The geomagnetic field responded with quiet to active levels on 20 Aug, quiet to unsettled levels on 21-22 Aug and quiet
levels on 23 Aug. By 24 Aug, a small discontinuity could be seen in the total field. A small increase to 7 nT was observed at 24/1116 UTC while the Bz component deflected southward to -6 nT, however the solar wind speed continued to decrease to near 325 km/s by the end of the day. As a result, quiet to unsettled levels were observed on 24 Aug. By 25 Aug, solar wind speed increased briefly to 460 km/s at 25/1305 UTC before declining once again, however total field began
to increase beginning at 25/1210 UTC as effects from the 20 Aug CME were beginning. By 26 Aug, total field increased to 18 nT and remained there for approximately 12 hours. The Bz component was
mostly negative reaching a maximum of -17 nT for approximately 24 hours beginning at 25/1600 UTC. Solar wind speed once again showed an increase at 26/0730 UTC from 370 km/s to near 550 km/s by the periods end as the solar wind stream was transitioning into a positive polarity CH HSS. The geomagnetic field responded with quiet to active levels on 25 Aug and unsettled to G3 (Strong) storm levels on 26 Aug.
Forecast of Solar and Geomagnetic Activity 27 August - 22 September 2018
Solar activity is expected to be at very low levels with a slight chance for C-class flare activity on 27-29 Aug and again on 11-22 Sep as Regions 2719 and 2720 return to the visible disk. Very low
levels are expected for the rest of 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 high levels on 27 Aug-03 Sep, 12-15 Sep, and again on 17-19 Sep due to recurrent CH HSS influence.
Geomagnetic field activity is expected to be at unsettled to active levels on 27-30 Aug, 01-02 Sep, 07 Sep, 11-17 Sep, and 22 Sep with G1 (Minor) geomagnetic storm levels expected early on 27 Aug due to CH HSS activity.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2018 Aug 27 0539 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC contact http://www.swpc.noaa.gov/wwire.html
#
# 27-day Space Weather Outlook Table
# Issued 2018-08-27
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2018 Aug 27 69 18 5
2018 Aug 28 69 8 3
2018 Aug 29 69 8 3
2018 Aug 30 67 8 3
2018 Aug 31 67 5 2
2018 Sep 01 67 8 3
2018 Sep 02 67 8 3
2018 Sep 03 67 5 2
2018 Sep 04 67 5 2
2018 Sep 05 67 5 2
2018 Sep 06 67 5 2
2018 Sep 07 67 8 3
2018 Sep 08 67 5 2
2018 Sep 09 67 5 2
2018 Sep 10 68 5 2
2018 Sep 11 68 15 4
2018 Sep 12 69 15 4
2018 Sep 13 70 12 4
2018 Sep 14 70 12 4
2018 Sep 15 70 10 3
2018 Sep 16 70 12 4
2018 Sep 17 70 8 3
2018 Sep 18 70 5 2
2018 Sep 19 70 5 2
2018 Sep 20 70 5 2
2018 Sep 21 70 5 2
2018 Sep 22 70 12 4
(NOAA)
