Subj : 3 Day Space Weather Forecast To : All From : Sean Dennis Date : Sun Sep 06 2026 12:19 am :Product: 3-Day Forecast :Issued: 2026 Sep 06 0030 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 06-Sep 08 2026 is 3.67 (below NOAA Scale levels). NOAA Kp index breakdown Sep 06-Sep 08 2026 Sep 06 Sep 07 Sep 08 00-03UT 1.67 3.33 3.33 03-06UT 1.67 2.00 4.00 06-09UT 1.33 2.00 3.67 09-12UT 1.33 3.00 3.33 12-15UT 1.33 3.67 3.00 15-18UT 1.33 3.33 3.00 18-21UT 1.33 3.33 2.67 21-00UT 1.67 3.00 3.00 Rationale: While a CIR ahead of a positive polarity coronal high speed stream and CME influences are anticipated to arrive on 07-08 Sep, no G1 (Minor) or greater geomagnetic storms are expected. B. NOAA Solar Radiation Activity Observation and Forecast Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was above S-scale storm level thresholds. Solar Radiation Storm Forecast for Sep 06-Sep 08 2026 Sep 06 Sep 07 Sep 08 S1 or greater 75% 10% 10% Rationale: S1 (Minor) solar radiation storms are expected on 06 Sep due to elevated levels from eruptive activity on 05 Sep, decreasing to a slight chance on 07-08 Sep, due to the source region remaining in a geo-effective location. C. 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 2026 1518 UTC. Radio Blackout Forecast for Sep 06-Sep 08 2026 Sep 06 Sep 07 Sep 08 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 08 Sep. --- MBSE BBS v1.1.7.2 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (1:18/200) .