3-Day Forecast

Issued: 2025 Dec 19 0030 UTC
Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center and processed by SpaceWeatherLive.com

A. NOAA Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 4 (below NOAA Scale levels).

The greatest expected 3 hr Kp for Dec 19-Dec 21 2025 is 3 (.00below NOAA Scale levels).

NOAA Kp index breakdown

             Dec 19       Dec 20       Dec 21
00-03UT       3.00         2.67         1.67     
03-06UT       3.00         2.67         1.33     
06-09UT       2.67         2.33         1.33     
09-12UT       2.00         1.67         1.33     
12-15UT       1.67         1.67         1.67     
15-18UT       1.33         1.33         1.33     
18-21UT       1.33         2.00         1.67     
21-00UT       2.67         2.00         1.33     

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 19-Dec 21 2025

              Dec 19  Dec 20  Dec 21
S1 or greater    1%      1%      1%

Rationale

No S1 (Minor) or greater solar radiation storms are expected. No significant active region activity favorable for radiation storm production is forecast.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Dec 19-Dec 21 2025

              Dec 19        Dec 20        Dec 21
R1-R2           15%           15%           15%
R3 or greater    1%            1%            1%

Rationale

There is a slight chance for R1-R2 (Minor-Moderate) radio blackouts through 20 Dec.