:Product: 3-Day Forecast :Issued: 2024 Apr 25 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 2 (below NOAA Scale levels). The greatest expected 3 hr Kp for Apr 25-Apr 27 2024 is 4.33 (below NOAA Scale levels). NOAA Kp index breakdown Apr 25-Apr 27 2024 Apr 25 Apr 26 Apr 27 00-03UT 3.00 4.33 3.67 03-06UT 2.67 4.00 3.33 06-09UT 3.67 3.33 2.00 09-12UT 4.33 3.00 3.00 12-15UT 3.67 2.67 2.67 15-18UT 3.33 2.67 3.00 18-21UT 2.67 2.00 3.00 21-00UT 4.00 3.33 3.33 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 Apr 25-Apr 27 2024 Apr 25 Apr 26 Apr 27 S1 or greater 15% 15% 15% Rationale: There is a slight chance of an S1 (Minor) solar radiation storm 24-26 Apr due to the favorable location and enhanced flare probabilities of a number of spot groups. 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 24 2024 2259 UTC. Radio Blackout Forecast for Apr 25-Apr 27 2024 Apr 25 Apr 26 Apr 27 R1-R2 75% 75% 75% R3 or greater 15% 15% 15% Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected, with a slight chance of an R3 (Strong) event due to the number of sunspots present on the solar disk and increased flare probabilities 24-26 Apr.