Weekly Space Weather Highlights

Highlights of Solar and Geomagnetic Activity
13 - 19 August 2018

Solar activity was very low. Two small regions developed on the
visible disk this period. Region 2718 (S07, L=191, class/area
Hrx/020 on 17 Aug) developed on 14 Aug and decayed to plage by 19
Aug. Region 2719 (S06, L=133, class/area Bxo/010 on 19 Aug)
developed in the SE quadrant on 19 Aug. No significant flare events
occurred from either region. Other activity included a filament
eruption centered near S11W04 observed lifting off the solar disk at
approximately 19/0538 UTC. An associated coronal mass ejection was
observed off the SW limb in SOHO/LASCO C2 imagery at 19/0812 UTC.
WSA/Enlil modelling of the event suggested the ejecta was primarily
directed westward of the Sun-Earth line and is not expected to cause
any significant effects. 

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
normal levels on 13-15 Aug, moderate levels on 16-17 Aug, and at
high levels on 18-19 Aug. The largest flux of the period was 18,287
pfu observed at 19/1800 UTC. 

Geomagnetic field activity ranged from quiet to active levels over
the period. Solar wind speed was at nominal levels at the beginning
of the period with solar wind speed ranging from 310-430 km/s while
total field was between 1-4 nT. The geomagnetic field was quiet on
13-14 Aug. By 15 Aug, solar wind speed increased to approximately
450-500 km/s with total field increasing to a maximum of 14 nT by
16/1005 UTC as a positive polarity coronal hole high speed stream
(CH HSS) moved into geoeffective position. A further increase in
solar wind speed to near 570 km/s was observed late on 17 Aug before
slowly receding to nominal levels by midday on 19 Aug. The
geomagnetic field responded with quiet to active levels on 15-18
Aug. By late on 19 Aug, total field increase again to 12 nT along
with an increase in solar wind to near 550 km/s as a negative
polarity CH HSS was becoming geoeffective. However, only quiet
levels were observed on 19 Aug. 

Forecast of Solar and Geomagnetic Activity
20 August - 15 September 2018

Solar activity is expected to continue at very low levels.

No proton events are expected at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit is
expected to reach high levels on 22-27 Aug and again on 13-15 Sep
due to CH HSS influence. 

Geomagnetic field activity is expected to be unsettled to active
levels on 20-25 Aug, 03-04 Sep, 07 Sep, and 11-15 Sep with a chance
for G1 (Minor) geomagnetic storm levels on 20-21 Aug due to
recurrent CH HSS activity.