Product: Weekly Highlights and Forecasts
:Issued: 2025 Sep 01 0133 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 - 25 - 31 August 2025
Solar activity was at low levels on 27 and 31 Aug. Activity reached moderate levels on 25, 26, and 28-30 Aug. Region 4197 (S17, L=131, class/area-Eki/720 on 27 Aug) produced six M-class flares, the largest being an M4.5/1n at 26/0525 UTC. Region 4199 (N04, L=115, class/area-Cao/200 on 26 Aug) produced five M-class flares, with its largest being an M4.5 flare as well, reaching a peak at 25/0524 UTC. This region was also responsible for a long-duration M2.7 flare at 30/1911 UTC. The associated full halo CME is forecast to arrive at Earth sometime late on 01 Sep into early on 02 Sep.
The greater than 10 MeV proton flux at geosynchronous orbit reached S1 (Minor) storm levels at 25/1355 UTC, observed a peak of 13 pfu at 27/0740 UTC, and decreased below threshold at 27/1510 UTC. Levels remained enhanced, but below the 10 pfu threshold, for the remainder of the period.
The greater then 2 MeV electron flux at geosynchronous orbit was at high levels on 25 Aug, but returned to normal to moderate levels from 26-31 Aug.
Geomagnetic field activity reached unsettled levels on 25-28 Aug and again on 31 Aug. Field activity was at low levels on 29-30 Aug.
Forecast of Solar and Geomagnetic Activity - 01 September - 27 September 2025
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Solar activity is expected to be at low levels, with varying chances for M-class flares (R1-R2/Minor-Moderate events) through 27 Sep.
The greater than 10 MeV proton flux levels are expected to be slightly enhanced, but below the 10 pfu level for 01-03 Sep. There is a chance levels could exceed the 10 pfu threshold on 01-02 Sep as the halo CME from 30 Aug passes Earth. Conditions are then likely to return to near background levels after 04 Sep, barring any additional strong flare events.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at moderate levels on 01-02 Sep, 15-19 Sep, and 22-27 Sep. Flux levels are expected to reach high levels on 03-14 Sep and 20-21 Sep in association with coronal hole (CH) high speed stream (HSS) influence.
Geomagnetic field activity is expected to reach G2 (Moderate) geomagnetic storm levels on 01 Sep, G3 (Strong) levels on 02 Sep, and active conditions on 03 Sep following the arrival of the halo CME from 30 Aug. Active conditions are likely on 06-10 Sep, and 15-19 Sep with CH HSS influence. Quiet to unsettled levels are
expected on 04-05 Sep, 11-14 Sep, and 20-27 Sep.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2025 Sep 01 0133 UTC
# Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center
# Product description and SWPC webcontact www.swpc.noaa.gov/content/subscription-services
# 27-day Space Weather Outlook Table
# Issued 2025-09-01
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2025 Sep 01 215 20 6
2025 Sep 02 210 55 7
2025 Sep 03 200 10 4
2025 Sep 04 195 5 2
2025 Sep 05 185 5 2
2025 Sep 06 175 8 3
2025 Sep 07 160 12 4
2025 Sep 08 140 12 4
2025 Sep 09 130 12 4
2025 Sep 10 125 10 4
2025 Sep 11 125 5 2
2025 Sep 12 120 5 2
2025 Sep 13 120 5 2
2025 Sep 14 120 5 2
2025 Sep 15 120 20 5
2025 Sep 16 125 15 4
2025 Sep 17 125 8 3
2025 Sep 18 130 10 4
2025 Sep 19 140 8 3
2025 Sep 20 150 8 3
2025 Sep 21 175 8 3
2025 Sep 22 180 8 3
2025 Sep 23 180 8 3
2025 Sep 24 180 5 2
2025 Sep 25 180 5 2
2025 Sep 26 180 5 2
2025 Sep 27 170 5 2
(NOAA)
