Product: 3-Day Forecast - Issued: 2026 Apr 25 1230 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center.

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 Apr 25-Apr 27 2026 is 4.67 (NOAA Scale G1).

Rationale: Isolated G1-G2 (Minor-Moderate) geomagnetic storming conditions are possible (G1 likely with a chance for G2) late on 25 Apr into early 26 Apr in response to the arrival of the glancing CMEs.

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.

Rationale: There is a chance for levels to exceed S1 (Minor) solar radiation storm thresholds due to the flare activity of Region 4419 as it rotates toward the western limb, and Region 4420 as it approaches central solar meridian. Chances diminish to a slight chance on 26-27 Apr.

Radio Blackout Activity and Forecast

Radio blackouts reaching the R2 levels were observed over the past 24 hours. The largest was at Apr 24 2026 1815 UTC.

Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely, with a chance for R3 (Strong or greater) events through 27 Apr, primarily driven by the complexity of Regions 4419, 4420, 4423, and 4425.