Credit: NASA/GSFC/TRACE
The greatest observed 3 hr Kp over the past 24 hours was 3 (below NOAA Scale levels).
The greatest expected 3 hr Kp for Sep 06-Sep 08 2025 is 5.00 (NOAA Scale G1).
NOAA Kp index breakdown Sep 06-Sep 08 2025
Sep 06 Sep 07 Sep 08
00-03UT 5.00 (G1) 3.67 3.00
03-06UT 4.67 (G1) 3.33 2.67
06-09UT 4.00 5.00 (G1) 2.00
09-12UT 4.00 5.00 (G1) 2.67
12-15UT 2.33 4.00 2.67
15-18UT 3.00 3.00 2.00
18-21UT 3.33 3.00 2.67
21-00UT 3.33 4.33 3.00
Rationale: G1 (Minor) or greater geomagnetic storms are likely on 06 Sep, due to influence from a coronal hole, and on 07 Sep due to arrival from a CME that left the Sun on 04 Sep.
NOAA Solar Radiation Activity Observation and Forecast
Solar radiation, as observed by over the past 24 hours, was below S-scale storm level thresholds. Solar Radiation Storm Forecast for Sep 06-Sep 08 2025
Sep 06 Sep 07 Sep 08
S1 or greater 10% 5% 5%
Rationale: There exists a slight chance for S1 (Minor) solar radiation storms over 06 Sep.
NOAA Radio Blackout Activity and Forecast
Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Sep 05 2025 0116 UTC.
Radio Blackout Forecast for Sep 06-Sep 08 2025
Sep 06 Sep 07 Sep 08
R1-R2 55% 40% 40%
R3 or greater 10% 5% 5%
Rationale: R1-R2 (Minor-Moderate) radio blackouts, with a slight chance for R3 (Strong), are like on 06 Sep. A chance remains for R1-R2 events over 07-08 Sep after multiple complex regions rotate around the Sun’s W limb.
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