Board: [DoveNet] HAM Radio Subject: 3 Day Space Weather Forec From: Sean Dennis Date: Mon May 11, 2026 01:19 @VIA: IISS :Product: 3-Day Forecast :Issued: 2026 May 11 0030 UTC # Prepared by the U.S. Dept. of Commerce, NOAA, Space WeatherPrediction Center # A. NOAA Geomagnetic Activity Observation and Forecast The greatest observed 3 hr Kp over the past 24 hours was 2 (below NOAA Scale levels). The greatest expected 3 hr Kp for May 11-May 13 2026 is 2.67 (below NOAA Scale levels). NOAAKp index breakdown May 11-May 13 2026 May 11 May 12 May 13 00-03UT 1.67 1.67 1.67 03-06UT 2.67 1.67 2.67 06-09UT 2.67 1.33 2.67 09-12UT 1.67 1.33 2.33 12-15UT 1.33 1.33 2.33 15-18UT 1.33 0.67 2.00 18-21UT 2.00 1.67 2.33 21-00UT 2.67 1.67 2.67 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-19 over the past 24 hours, was below S-scale storm level thresholds. Solar Radiation Storm Forecast for May 11-May 13 2026 May 11 May 12 May 13 S1 or greater 20% 20% 20% Rationale: No S1 (Minor) or greater solar radiation storms are expected. No significant activeregion activity favorable for radiation storm production is forecast. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R2 levels were observed over the past 24 hours. The largest was at May 10 2026 1339 UTC. Radio Blackout Forecast for May 11-May 13 2026 May 11 May 12 May 13 R1-R2 45% 45% 45% R3or greater 20% 20% 20% Rationale: There exists a chance for R1-R2 (Minor-Moderate) radio blackouts, witha slight chance for R3 (Strong), over 11-13 May. --- MBSE BBS v1.1.7.2 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (1:18/200) .