384
FXXX10 KWNP 071231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Dec 07 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 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Dec 07-Dec 09 2025 is 6.67 (NOAA Scale
G3).

NOAA Kp index breakdown Dec 07-Dec 09 2025

             Dec 07       Dec 08       Dec 09
00-03UT       2.67         3.00         1.67
03-06UT       3.67         5.00 (G1)    1.67
06-09UT       3.00         3.00         4.00
09-12UT       2.00         3.00         6.67 (G3)
12-15UT       2.33         3.67         6.67 (G3)
15-18UT       3.67         2.67         5.67 (G2)
18-21UT       5.00 (G1)    2.00         5.67 (G2)
21-00UT       4.00         2.00         5.33 (G1)

Rationale: Isolated periods of G1 (Minor) geomagnetic storming are
likely on 07-08 Dec due to the anticipated glancing arrival of a CME
from 04 Dec. Periods of G1 (Minor), G2 (Moderate) and G3 (Strong)
geomagnetic storming are likely on 09 Dec due to the anticipated arrival
of a CME from 06 Dec.

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 07-Dec 09 2025

              Dec 07  Dec 08  Dec 09
S1 or greater   10%     10%     10%

Rationale: There is a slight chance for S1 (Minor) solar radiation storm
conditions on 07-09 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 06 2025 2039 UTC.

Radio Blackout Forecast for Dec 07-Dec 09 2025

              Dec 07        Dec 08        Dec 09
R1-R2           65%           65%           65%
R3 or greater   15%           15%           15%

Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely, with a
slight chance for R3 (Strong) or greater events, on 07-09 Dec.