:Product: 3-Day Forecast :Issued: 2026 Jun 07 1230 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 3 (below NOAA Scale levels). The greatest expected 3 hr Kp for Jun 07-Jun 09 2026 is 7.00 (NOAA Scale G3). NOAA Kp index breakdown Jun 07-Jun 09 2026 Jun 07 Jun 08 Jun 09 00-03UT 2.67 2.33 6.33 (G2) 03-06UT 2.00 2.00 5.33 (G1) 06-09UT 2.00 3.00 5.00 (G1) 09-12UT 2.67 4.33 4.33 12-15UT 2.00 5.33 (G1) 3.00 15-18UT 2.00 5.67 (G2) 3.33 18-21UT 2.33 7.00 (G3) 3.33 21-00UT 2.33 6.33 (G2) 3.67 Rationale: Periods of G1-G3 (Minor-Strong) geomagnetic storming are likely on 08 Jun, with G1-G2 (Minor-Moderate) storm periods likely on 09 Jun, following the anticipated arrival of a CME that left the Sun on 06 Jun. 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 Jun 07-Jun 09 2026 Jun 07 Jun 08 Jun 09 S1 or greater 15% 25% 10% Rationale: There is a slight chance for S1 (Minor) solar radiation storms on 07 and 09 Jun, with a chance for S1 levels on 08 Jun following the anticipated shock arrival of the 06 June CME. C. NOAA Radio Blackout Activity and Forecast Radio blackouts reaching the R1 levels were observed over the past 24 hours. The largest was at Jun 06 2026 1401 UTC. Radio Blackout Forecast for Jun 07-Jun 09 2026 Jun 07 Jun 08 Jun 09 R1-R2 55% 55% 55% R3 or greater 10% 10% 10% Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely, with a slight chance for R3 (Strong) or greater events, over 07-09 Jun.