FXXX10 KWNP 100031 DAYTDF :Product: 3-Day Forecast :Issued: 2025 May 10 0030 UTC # Prepared by the US Dept. of Commerce, NOAA, Space Weather Prediction Center # Product description and SWPC contact on the Web # http://www.swpc.noaa.gov/wwire.html # # 3-Day Forecast # 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 May 10-May 12 2025 is 4.67 (NOAA Scale G1). NOAA Kp index breakdown May 10-May 12 2025 May 10 May 11 May 12 00-03UT 4.67 (G1) 3.00 2.33 03-06UT 4.67 (G1) 3.67 2.67 06-09UT 2.67 2.67 2.00 09-12UT 2.00 2.00 1.00 12-15UT 2.67 2.00 0.67 15-18UT 2.00 2.67 2.33 18-21UT 2.67 2.67 2.67 21-00UT 2.67 2.67 2.33 Rationale: Isolated G1 (Minor) storming periods early on 10 May due to negative polarity CH HSS influences and the possible arrival of a CME from 05 May. 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 May 10-May 12 2025 May 10 May 11 May 12 S1 or greater 5% 5% 1% Rationale: No S1 (Minor) or greater solar radiation storms are expected. No significant active region activity favorable for radiation storm production is forecast. C. NOAA Radio Blackout Activity and Forecast No radio blackouts were observed over the past 24 hours. Radio Blackout Forecast for May 10-May 12 2025 May 10 May 11 May 12 R1-R2 40% 40% 10% R3 or greater 5% 5% 1% Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts over 10-11 May, decreasing to a slight chance on 12 May.