Subj : 3 Day Space Weather Forecast To : All From : Sean Dennis Date : Tue Apr 15 2025 12:19 am :Product: 3-Day Forecast :Issued: 2025 Apr 15 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 4 (below NOAA Scale levels). The greatest expected 3 hr Kp for Apr 15-Apr 17 2025 is 6.00 (NOAA Scale G2). NOAA Kp index breakdown Apr 15-Apr 17 2025 Apr 15 Apr 16 Apr 17 00-03UT 3.67 4.00 4.33 03-06UT 3.00 3.00 4.33 06-09UT 3.00 5.00 (G1) 4.00 09-12UT 3.67 4.00 3.67 12-15UT 2.67 6.00 (G2) 4.33 15-18UT 2.00 4.00 3.00 18-21UT 2.00 5.00 (G1) 2.67 21-00UT 3.67 4.33 4.00 Rationale: G1-G2 (Minor-Moderate) storming is likely on 16 Apr due to CME arrival from filament eruptions that left the Sun on 13 Apr. 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 Apr 15-Apr 17 2025 Apr 15 Apr 16 Apr 17 S1 or greater 10% 10% 5% Rationale: There is a slight chance for S1 (minor) solar radiation storms on 15-16 Apr. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Apr 14 2025 0650 UTC. Radio Blackout Forecast for Apr 15-Apr 17 2025 Apr 15 Apr 16 Apr 17 R1-R2 80% 75% 60% R3 or greater 15% 10% 10% Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected on 16-17 Apr, with a slight chance for R3 (Strong) events. Probabilities decrease slightly on 17 Apr. --- MBSE BBS v1.1.1 (Linux-x86_64) * Origin: Outpost BBS * Johnson City, TN (1:18/200) .