423
FXXX10 KWNP 241231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Apr 24 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 24-Apr 26 2026 is 4.67 (NOAA Scale
G1).

NOAA Kp index breakdown Apr 24-Apr 26 2026

             Apr 24       Apr 25       Apr 26
00-03UT       2.67         3.00         3.67
03-06UT       1.33         2.67         3.33
06-09UT       2.33         2.33         3.00
09-12UT       1.33         2.00         2.33
12-15UT       1.33         2.00         3.67
15-18UT       2.00         2.33         4.67 (G1)
18-21UT       2.00         3.33         4.33
21-00UT       2.33         3.67         3.33

Rationale: Isolated G1-G2 (Minor-Moderate) geomagnetic storming
conditions are possible 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 24-Apr 26 2026

              Apr 24  Apr 25  Apr 26
S1 or greater   25%     25%     20%

Rationale: There is a chance for S1 (Minor) solar radiation storms due
to the flare activity of Region 4419 as it rotates toward the western
limb and Region 4420 as it approaches central solar meridian.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R3 levels were observed over the past 24
hours. The largest was at Apr 24 2026 0813 UTC.

Radio Blackout Forecast for Apr 24-Apr 26 2026

              Apr 24        Apr 25        Apr 26
R1-R2           75%           75%           75%
R3 or greater   35%           35%           30%

Rationale: (R1-R2-Moderate) radio blackouts are expected through 26 Apr,
with a chance for R3 (Strong or greater) radio blackouts, primarily
driven by the ongoing complexity of Regions 4419 and 4420.