938
FXXX10 KWNP 280031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Dec 28 0030 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 Dec 28-Dec 30 2025 is 1.67 (below NOAA
Scale levels).

NOAA Kp index breakdown Dec 28-Dec 30 2025

             Dec 28       Dec 29       Dec 30
00-03UT       1.67         1.67         1.33
03-06UT       1.33         1.33         1.33
06-09UT       1.33         1.33         1.33
09-12UT       1.33         1.33         1.33
12-15UT       1.33         1.33         1.67
15-18UT       1.67         1.33         1.33
18-21UT       1.33         1.67         1.67
21-00UT       1.67         1.67         1.67

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 Dec 28-Dec 30 2025

              Dec 28  Dec 29  Dec 30
S1 or greater   15%     10%     10%

Rationale: There is a slight chance for the greater than 10 MeV proton
flux to reach S1 (Minor) storm levels on 28-30 Dec.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R2 levels were observed over the past 24
hours. The largest was at Dec 27 2025 0150 UTC.

Radio Blackout Forecast for Dec 28-Dec 30 2025

              Dec 28        Dec 29        Dec 30
R1-R2           65%           65%           65%
R3 or greater   20%           20%           20%

Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely on 28-30
Dec, with a slight chance for an isolated R3 (Strong) or greater event.