477
FXXX10 KWNP 160031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Dec 16 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 16-Dec 18 2025 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Dec 16-Dec 18 2025

             Dec 16       Dec 17       Dec 18
00-03UT       1.67         1.67         5.00 (G1)
03-06UT       3.00         2.00         4.67 (G1)
06-09UT       2.67         2.00         4.00
09-12UT       2.00         2.00         3.67
12-15UT       2.00         3.00         3.00
15-18UT       1.33         3.33         3.00
18-21UT       0.67         4.00         2.67
21-00UT       1.67         4.33         3.33

Rationale: G1 (Minor) or greater geomagnetic storms are expected on Dec
18 due to the passage of a coronal hole high speed stream.

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 16-Dec 18 2025

              Dec 16  Dec 17  Dec 18
S1 or greater    1%      1%      1%

Rationale: No S1 (Minor) or greater solar radiation storms are expected.


C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Dec 16-Dec 18 2025

              Dec 16        Dec 17        Dec 18
R1-R2           20%           20%           20%
R3 or greater    1%            1%            1%

Rationale: No R1 (Minor) or greater radio blackouts are expected.  No
significant active region flare activity is forecast.