:Product: Weekly Highlights and Forecasts
:Issued: 2021 Sep 13 0136 UTC
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#                Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
06 - 12 September 2021

Solar activity was at low levels with C-class activity observed from
three separate regions. Region 2864 (N24, L=249, class/area Cso/120
on 07 Sep) produced a C2/Sf event at 08/0009 UTC. Associated with
this flare was Type II (723 km/s shock velocity) and Type IV radio
signatures, along with a weak, Earth-directed CME. Region 2866 (S18,
L=199, class/area Dkc/500 on 09 Sep) produced four C-class events
including the largest of the period; a C8/1n at 08/1730 UTC. Region
2868 (S21, L=213, class/area Dhi/300 on 08 Sep) also produced four
C-class flares during the period. 

No proton events were observed at geosynchronous orbit.

The greater than 2 MeV electron flux at geosynchronous orbit was at
high levels on 06-07 Sep with a peak of 3,280 pfu observed at
06/1615 UTC. Normal to moderate levels were observed on 08-12 Sep. 

Geomagnetic field activity was at quiet to isolated active levels
during the period. Quiet to active conditions were observed on 06-08
Sep due to weak, positive polarity CH HSS influence. Quiet levels
were observed on 09 Sep through a majority of 10 Sep. Unsettled to
active conditions were observed on late 10 Sep through early on 11
Sep due to weak influence from the 08 Sep CME. Quiet conditions were
observed for the remainder of 11 Sep through 12 Sep. 

Forecast of Solar and Geomagnetic Activity
13 September - 09 October 2021

Solar activity is expected to be at low levels, with a slight chance
for M-class activity, on 13-16 Sep due to potential flare activity
from Regions 2866 and 2868. Very low to low activity is expected
from 17-28 Sep. A return to low levels, with a slight chance for
M-class activity, is possible on 29 Sep - 09 Oct upon the return of
old Regions 2866 and 2868. 

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 on 13 Sep - 04 Oct and
08-09 Oct. Moderate to high levels are possible on 05-07 Oct due to
CH HSS influence. 

Geomagnetic field activity is expected to be at unsettled levels on
21 Sep and unsettled to active levels on 04-05 Oct, all due to
positive polarity CH HSS influence. The remainder of the outlook
period is expected to be at mostly quiet levels.