FXXX10 KWNP 041231 DAYTDF :Product: 3-Day Forecast :Issued: 2026 May 04 1230 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 2 (below NOAA Scale levels). The greatest expected 3 hr Kp for May 04-May 06 2026 is 2.67 (below NOAA Scale levels). NOAA Kp index breakdown May 04-May 06 2026 May 04 May 05 May 06 00-03UT 2.00 2.00 1.67 03-06UT 2.33 2.67 2.00 06-09UT 2.00 1.67 2.67 09-12UT 2.67 1.67 1.67 12-15UT 1.67 1.00 0.67 15-18UT 1.67 0.67 0.67 18-21UT 0.67 1.00 1.67 21-00UT 2.00 1.67 1.67 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-18 over the past 24 hours, was below S-scale storm level thresholds. Solar Radiation Storm Forecast for May 04-May 06 2026 May 04 May 05 May 06 S1 or greater 5% 1% 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 Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at May 04 2026 0133 UTC. Radio Blackout Forecast for May 04-May 06 2026 May 04 May 05 May 06 R1-R2 40% 35% 35% R3 or greater 5% 5% 5% Rationale: A chance for isolated R1-R2 (Minor-Moderate) radio blackouts due to isolated M-class flare activity will persist through 06 May. Probabilities decrease slightly beginning on 05 May as AR 4424 departs the western limb.