:Product: 3-Day Forecast
:Issued: 2026 Sep 05 1230 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
A. NOAA Geomagnetic Activity Observation and Forecast

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 05-Sep 07 2026 is 3.67 (below NOAA
Scale levels).

NOAA Kp index breakdown Sep 05-Sep 07 2026

             Sep 05       Sep 06       Sep 07
00-03UT       2.00         1.67         3.33     
03-06UT       2.67         1.67         2.00     
06-09UT       2.00         1.33         2.00     
09-12UT       2.00         1.33         3.00     
12-15UT       1.67         1.33         3.67     
15-18UT       2.00         1.33         3.33     
18-21UT       2.00         1.33         3.33     
21-00UT       2.00         1.67         3.00     

Rationale: No G1 (Minor) or greater geomagnetic storms are expected.  No
significant transient or recurrent solar wind features are forecast.

B. NOAA Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
below S-scale storm level thresholds.

Solar Radiation Storm Forecast for Sep 05-Sep 07 2026

              Sep 05  Sep 06  Sep 07
S1 or greater    1%      1%      1%

Rationale: No S1 (Minor) or greater solar radiation storms are expected.
No significant active region activity favorable for radiation storm
production is forecast.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Sep 05-Sep 07 2026

              Sep 05        Sep 06        Sep 07
R1-R2           20%           20%           20%
R3 or greater    1%            1%            1%

Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio
blackouts through 07 Sep.