925
FXXX10 KWNP 281231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Apr 28 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 Apr 28-Apr 30 2026 is 4.00 (below NOAA
Scale levels).

NOAA Kp index breakdown Apr 28-Apr 30 2026

             Apr 28       Apr 29       Apr 30
00-03UT       0.67         2.00         4.00
03-06UT       0.67         2.33         3.33
06-09UT       0.67         1.67         2.67
09-12UT       1.00         1.33         3.00
12-15UT       1.67         2.00         2.33
15-18UT       1.67         3.00         2.33
18-21UT       1.67         3.33         2.00
21-00UT       2.00         4.00         3.00

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 28-Apr 30 2026

              Apr 28  Apr 29  Apr 30
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 28-30 Apr.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Apr 28-Apr 30 2026

              Apr 28        Apr 29        Apr 30
R1-R2           70%           70%           70%
R3 or greater   25%           25%           25%

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