407
FXXX10 KWNP 030031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Dec 03 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 03-Dec 05 2025 is 5.67 (NOAA Scale
G2).

NOAA Kp index breakdown Dec 03-Dec 05 2025

             Dec 03       Dec 04       Dec 05
00-03UT       3.00         4.67 (G1)    4.33
03-06UT       3.67         4.67 (G1)    4.33
06-09UT       3.00         5.67 (G2)    4.33
09-12UT       3.00         4.33         4.00
12-15UT       3.00         3.67         3.67
15-18UT       3.33         3.67         3.33
18-21UT       4.33         4.00         3.00
21-00UT       5.67 (G2)    4.33         3.33

Rationale: G1-G2 (Minor-Moderate) geomagnetic storming is likely to
commence by late on 03 Dec and continue into 04 Due due to coronal hole
high speed stream effects possibly combined with glancing shock arrival
from a coronal mass ejection that left the Sun on 01 Dec. It should also
be noted that a chance (25%) for isolated periods of G3 (Strong)
geomagnetic storming will exist on late 03 Dec and early 04 Dec,
especially if the corotating interaction region ahead of the high speed
stream arrives with embedded shock.

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 03-Dec 05 2025

              Dec 03  Dec 04  Dec 05
S1 or greater   15%     15%     15%

Rationale: There is a slight chance for an S1 (Minor) solar radiation
storm on 03-05 Dec.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Dec 03-Dec 05 2025

              Dec 03        Dec 04        Dec 05
R1-R2           75%           75%           75%
R3 or greater   30%           30%           30%

Rationale: Isolated to occasional M-class flares (R1-R2, Minor-Moderate)
are expected (75%) through 05 Dec, with a chance for X-class flares
(R3-Strong 30%), given past flare history and the potential of current
active regions on the disk.