FXXX10 KWNP 101231 DAYTDF :Product: 3-Day Forecast :Issued: 2024 May 10 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 3 (below NOAA Scale levels). The greatest expected 3 hr Kp for May 10-May 12 2024 is 8.33 (NOAA Scale G4). NOAA Kp index breakdown May 10-May 12 2024 May 10 May 11 May 12 00-03UT 3.00 5.33 (G1) 4.67 (G1) 03-06UT 3.00 7.00 (G3) 5.67 (G2) 06-09UT 2.67 8.33 (G4) 4.67 (G1) 09-12UT 2.33 6.67 (G3) 4.00 12-15UT 2.67 5.67 (G2) 3.67 15-18UT 3.67 5.00 (G1) 2.67 18-21UT 4.33 4.67 (G1) 2.67 21-00UT 5.33 (G1) 4.33 3.67 Rationale: G1-2 (Minor-Moderate) geomagnetic storming is likely on 10-12 May due to multiple CMEs from AR 3634 spanning 08-10 May. G3 (Strong) to G4 (Severe or greater) geomagnetic storming is likely on 11 May as the bulk of the activity is expected to arrive during the early hours of the UTC day. 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 2024 May 10 May 11 May 12 S1 or greater 55% 55% 55% Rationale: S1-2 (Minor-Moderate) solar radiation storms are likely through the forecast period due to the potential exhibited by AR 3634. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R3 levels were observed over the past 24 hours. The largest was at May 10 2024 0654 UTC. Radio Blackout Forecast for May 10-May 12 2024 May 10 May 11 May 12 R1-R2 95% 95% 95% R3 or greater 75% 75% 75% Rationale: R3 (Strong or greater) radio blackouts due to isolated X-class flare activity are expected to continue through the forecast period primarily due to potential from AR 3634.