roduct: 3-Day Forecast
:Issued: 2026 Apr 29 0030 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 1 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Apr 29-May 01 2026 is 4.00 (below NOAA
Scale levels).

NOAA Kp index breakdown Apr 29-May 01 2026

             Apr 29       Apr 30       May 01
00-03UT       0.33         4.00         3.00     
03-06UT       0.67         3.33         2.67     
06-09UT       1.33         2.67         2.67     
09-12UT       1.33         3.00         2.33     
12-15UT       1.00         2.33         2.00     
15-18UT       1.00         2.33         2.00     
18-21UT       1.33         2.00         2.00     
21-00UT       1.67         3.00         2.33     

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 Apr 29-May 01 2026

              Apr 29  Apr 30  May 01
S1 or greater   15%     15%     15%

Rationale: There is a slight chance the greater than 10 MeV proton flux
could reach S1 (Minor) levels, but is mainly expected to remain at
background levels 29-30 Apr and 01 May.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Apr 28 2026 1353 UTC.

Radio Blackout Forecast for Apr 29-May 01 2026

              Apr 29        Apr 30        May 01
R1-R2           70%           70%           70%
R3 or greater   20%           20%           20%

Rationale: There is a high likelihood for R1/R2 (Minor/Moderate) radio
blackouts, and a slight chance for R3 (Strong or greater) events through
01 May, due primarily to the complexity of regions 4420 and 4425.


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