373
FXXX10 KWNP 251231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Apr 25 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 Apr 25-Apr 27 2026 is 4.67 (NOAA Scale
G1).

NOAA Kp index breakdown Apr 25-Apr 27 2026

             Apr 25       Apr 26       Apr 27
00-03UT       3.33         4.67 (G1)    2.67
03-06UT       1.33         4.33         2.67
06-09UT       1.33         3.67         2.33
09-12UT       0.67         3.00         2.33
12-15UT       2.00         3.00         2.33
15-18UT       2.67         2.33         2.33
18-21UT       4.33         2.67         2.33
21-00UT       4.67 (G1)    3.00         2.00

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.

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 25-Apr 27 2026

              Apr 25  Apr 26  Apr 27
S1 or greater   25%     20%     10%

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.

C. NOAA 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.

Radio Blackout Forecast for Apr 25-Apr 27 2026

              Apr 25        Apr 26        Apr 27
R1-R2           65%           60%           55%
R3 or greater   35%           25%           20%

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.