Subj : 3 Day Space Weather Forecast To : All From : Sean Dennis Date : Fri Aug 28 2026 12:19 am :Product: 3-Day Forecast :Issued: 2026 Aug 28 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 1 (below NOAA Scale levels). The greatest expected 3 hr Kp for Aug 28-Aug 30 2026 is 5.67 (NOAA Scale G2). NOAA Kp index breakdown Aug 28-Aug 30 2026 Aug 28 Aug 29 Aug 30 00-03UT 2.33 5.67 (G2) 3.67 03-06UT 2.67 4.67 (G1) 3.33 06-09UT 4.00 4.00 3.00 09-12UT 4.00 3.00 3.00 12-15UT 4.67 (G1) 2.33 3.00 15-18UT 5.00 (G1) 2.67 2.00 18-21UT 4.67 (G1) 2.67 3.33 21-00UT 5.67 (G2) 3.00 3.33 Rationale: G1 (Minor) storm levels are likely due to the onset of positive polarity CH HSS effects. Later on 28 Aug, G2 (Moderate) storm levels are likely due to additional disturbances caused by the anticipated arrival of the CMEs that left the Sun on 25-26 Aug. G1 to G2 storm levels are likely to persist through 29 Aug before waning conditions are expected on 30 Aug. 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 Aug 28-Aug 30 2026 Aug 28 Aug 29 Aug 30 S1 or greater 10% 10% 10% Rationale: here is a slight chance for the greater than 10 MeV proton flux to reach S1 (Minor) storm levels through 30 Aug, mostly due to the potential for activity from Region 4513. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for Aug 28-Aug 30 2026 Aug 28 Aug 29 Aug 30 R1-R2 45% 45% 45% R3 or greater 10% 10% 10% Rationale: There is a chance for isolated R1/R2 (Minor-Moderate) radio blackouts, with a slight chance for an isolated R3 (Strong) event through 30 Aug primarily due to the current potential and flare history of Region 4513. --- MBSE BBS v1.1.7.2 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (1:18/200) .