FXXX10 KWNP 110031

DAYTDF



:Product: 3-Day Forecast

:Issued: 2025 Dec 11 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 6 (NOAA Scale

G2). The greatest expected 3 hr Kp for Dec 11-Dec 13 2025 is 5.67 (NOAA

Scale G2).



NOAA Kp index breakdown Dec 11-Dec 13 2025



             Dec 11       Dec 12       Dec 13

00-03UT       5.67 (G2)    3.33         2.67     

03-06UT       5.00 (G1)    2.00         2.33     

06-09UT       4.00         2.00         2.33     

09-12UT       2.33         3.00         1.67     

12-15UT       2.33         2.67         2.00     

15-18UT       2.33         3.00         2.67     

18-21UT       2.33         3.33         3.33     

21-00UT       2.67         3.33         3.67     



Rationale: G1-G2 (Minor-Moderate) geomagnetic storms are expected due to

the influence of ongoing solar wind transients near Earth, likely

associated with a CME partial hit.



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 11-Dec 13 2025



              Dec 11  Dec 12  Dec 13

S1 or greater   15%     10%      5%



Rationale: There is a slight chance for S1 (Minor) or greater solar

radiation storms on 11-12 Dec.



C. NOAA Radio Blackout Activity and Forecast



Radio blackouts reaching the R1 levels were observed over the past 24

hours. The largest was at Dec 10 2025 2208 UTC.



Radio Blackout Forecast for Dec 11-Dec 13 2025



              Dec 11        Dec 12        Dec 13

R1-R2           75%           65%           65%

R3 or greater   15%           10%            5%



Rationale: R1-R2 (Minor-Moderate) radio blackouts are expected on 11 Dec

and likely on 12-13 Dec. There is a slight chance of R3 (Strong) or

greater storms on 11-12 Dec.