Product: Weekly Highlights and Forecasts
:Issued: 2025 Aug 25 0309 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 18 - 24 August 2025
Solar activity was at low levels on 18, 20, and 21 Aug with only C-class flares observed. Activity increased to moderate levels on 19 Aug following an M1.1 flare at 19/0439 UTC from an area beyond the Eastern limb. Moderate levels were also observed on 22 Aug as Region 4191 (N11, L=172, class/area=Ehi/360 on 24 Aug) produced a long-duration M1.7/Sf flare at 22/1851 UTC. Associated with this flare was a Type II radio sweep with an estimated shock speed of 521 km/s. The associated CME was deemed to be behind the Sun-Earth line. Moderate levels continued into 23 and 24 Aug with an M1.9 at 23/2006 UTC and an M1.3 flare at 24/0836 UTC, both originating from beyond the NE limb. While multiple CMEs were observed in coronagraph imagery over the period, nearly all were at or beyond the Eastern limb and none were considered to have an Earth-directed component.
The greater than 10 MeV proton flux at geosynchronous orbit was at background levels from 18-22 Aug. Beginning around midday on 22 Aug, flux levels began to rise following the long-duration M1.7 flare event, mentioned above. Levels continued to rise, eventually reaching a peak of 8.3 pfu at 24/2330 UTC, but never exceeded the greater than 10 pfu levels.
The greater than 2 MeV electron flux at geosynchronous orbit was at normal to moderate levels on 19-20 Aug, and 22-23 Aug. Activity reached high levels on 18, 21, and 24 Aug, with the peak observed value of 2,200 pfu at 18/0830 UTC.
Geomagnetic field activity was at quiet to unsettled levels on 18 and 24 Aug, bookending a negative polarity coronal hole high speed stream. Unsettled to active conditions were observed on 20-23 Aug as CH HSS activity elevated, with active to minor storm levels observed on 19 Aug.
Forecast of Solar and Geomagnetic Activity 25 August - 20 September 2025
Solar activity is expected to be at low levels, with varying chances for M-class flares (R1-R2/Minor-Moderate events) through 20 Sep.
The greater than 10 MeV proton levels are expected to be at or above 10 pfu levels on 25 Aug before dropping below the 10 pfu level by 26 Aug. Levels should remain below thresholds through 20 Sep, with no additional events expected at geosynchronous orbit.
The greater than 2 MeV electron flux at geosynchronous orbit is expected to be at moderate levels on 25-26 Aug, 29 Aug-5 Sep, and 15-19 Sep. Conditions are likely to see high levels on 27-28 Aug, 6-14 Sep, and again on 20 Sep.
Geomagnetic field activity is expected to be at mostly quiet levels on 29 Aug-3 Sep and again on 11-14 Sep. Unsettled levels are likely on 25-28 Aug, 7-10 Sep, and 17-20 Sep. Active conditions are likely on 4-9 Sep and 15-16 Sep, with possible minor storming on 4-6 Sep and 15 Sep. All increased activity levels are associated with coronal hole high speed stream influence.
Product: 27-day Space Weather Outlook Table 27DO.txt
:Issued: 2025 Aug 18 0120 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
#
# 27-day Space Weather Outlook Table
# Issued 2025-08-18
#
# UTC Radio Flux Planetary Largest
# Date 10.7 cm A Index Kp Index
2025 Aug 18 115 12 3
2025 Aug 19 110 30 5
2025 Aug 20 110 18 4
2025 Aug 21 110 8 3
2025 Aug 22 110 8 3
2025 Aug 23 120 5 2
2025 Aug 24 125 5 2
2025 Aug 25 120 8 3
2025 Aug 26 120 8 3
2025 Aug 27 125 10 3
2025 Aug 28 125 12 4
2025 Aug 29 130 8 3
2025 Aug 30 130 10 3
2025 Aug 31 140 10 3
2025 Sep 01 150 8 3
2025 Sep 02 150 5 2
2025 Sep 03 140 5 2
2025 Sep 04 140 20 4
2025 Sep 05 135 35 6
2025 Sep 06 130 20 4
2025 Sep 07 130 15 3
2025 Sep 08 130 15 3
2025 Sep 09 120 15 3
2025 Sep 10 120 10 3
2025 Sep 11 115 5 2
2025 Sep 12 110 5 2
2025 Sep 13 110 5 2
(NOAA)
