Monday, August 31, 2026

Weekly Propagation Forecast Bulletins-31 August 2026

 Product: Weekly Highlights and Forecasts
:Issued: 2026 Aug 31 0155 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web contact www.swpc.noaa.gov/content/subscription-services
#
#                Weekly Highlights and Forecasts
#
Highlights of Solar and Geomagnetic Activity
24 - 30 August 2026


Solar activity was at very low to low levels from 27-30 Aug, reached
R1 (Minor) levels on 24 and 26 Aug, and peaked at R2 (Moderate)
levels on 25 Aug. Region 4513 (N04, L=54, class/area Ekc/310 on 25
Aug) was responsible for all seven of the M-class
(R1/R2-Minor/Moderate) flares throughout the period. The largest
event was an M6.9/1b (R2) flare that peaked at 25/1002 UTC. This
flare was accompanied by a Type II radio sweep, estimated speed of
603 km/s, a 160 sfu F10.7 cm radio burst, and a CME first observed
in LASCO C2 imagery at ~25/1100 UTC. Analysis of the CME indicated
possible impacts at Earth on 28 Aug. Region 4513 also produced an
M2.2/1b flare at 26/034 UTC that had a corresponding Type II radio
sweep, estimated speed of 930 km/s, and a potentially Earth-directed
CME. Analysis indicated the likely arrival window for the CMEs was on
28-29 Aug. Region 4315 also contributed 14 C-class flares throughout
the period. 

No proton events exceeding the S1 (Minor) alert threshold were
observed at geosynchronous orbit. However, flux levels were elevated
to near 7 nT and remained elevated from 24-26 Aug, after which they
returned to near background conditions. 

The greater than 2 MeV electron flux at geosynchronous orbit was
high levels from 24-28 Aug, then returned to normal to moderate
levels from 29-30 Aug. 

Geomagnetic field activity was at unsettled levels on 24 Aug, quiet
levels on 25-27 Aug, and reached active levels on 28-30 Aug under
positive polarity coronal hole high speed stream influence. 

Forecast of Solar and Geomagnetic Activity
31 August - 26 September 2026

Solar activity is expected to be at very low to low levels, with a
chance for moderate levels and a slight chance for high levels
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 high levels on 31 Aug - 06 Sep, then again from
16-23 Sep. Levels are expected to be at normal to moderate levels
from 07 - 15 Sep, and again from 24-26 Sep. 

Geomagnetic field activity is expected to decrease from unsettled
levels on 31 Aug to mostly quiet levels from 01-11 Sep and again
from 17-23 Sep. Unsettled to active conditions are expected from
12-16 Sep due to negtive polarity CH HSS influence, then again from
24-26 Sep under positive polarity CH HSS influence. 

Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2026 Aug 31 0155 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC web ontact  www.swpc.noaa.gov/content/subscription-services
#
#      27-day Space Weather Outlook Table
#                Issued 2026-08-31
#
#   UTC      Radio Flux   Planetary   Largest
#  Date       10.7 cm      A Index    Kp Index
2026 Aug 31     110          12          3
2026 Sep 01     105           5          2
2026 Sep 02     105           5          2
2026 Sep 03     100           5          2
2026 Sep 04     100           5          2
2026 Sep 05      95           5          2
2026 Sep 06      95           5          2
2026 Sep 07      95           5          2
2026 Sep 08      95           5          2
2026 Sep 09     100           5          2
2026 Sep 10     100           5          2
2026 Sep 11     100           5          2
2026 Sep 12     105           8          3
2026 Sep 13     110          15          3
2026 Sep 14     110          12          3
2026 Sep 15     100           8          3
2026 Sep 16      95           8          3
2026 Sep 17     100           5          2
2026 Sep 18     100           5          2
2026 Sep 19      95           5          2
2026 Sep 20      95           5          2
2026 Sep 21      95           5          2
2026 Sep 22      95           4          2
2026 Sep 23      92           4          2
2026 Sep 24      92          20          4
2026 Sep 25      92          22          5
2026 Sep 26      90          22          5
(NOAA)