:Product: 3-Day Forecast
:Issued: 2025 Oct 31 1230 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
A. NOAA Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 5 (NOAA Scale
G1).
The greatest expected 3 hr Kp for Oct 31-Nov 02 2025 is 4.67 (NOAA Scale
G1).

NOAA Kp index breakdown Oct 31-Nov 02 2025

             Oct 31       Nov 01       Nov 02
00-03UT       4.33         4.00         3.33     
03-06UT       4.67 (G1)    3.33         4.00     
06-09UT       4.33         3.33         3.33     
09-12UT       3.67         3.00         2.67     
12-15UT       4.67 (G1)    3.67         2.33     
15-18UT       3.00         2.67         2.00     
18-21UT       3.33         2.67         2.33     
21-00UT       4.00         3.33         3.33     

Rationale: G1 (Minor) geomagnetic storm levels are expected on 31 Oct
due to persistent CH HSS effects.

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 Oct 31-Nov 02 2025

              Oct 31  Nov 01  Nov 02
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 Oct 31-Nov 02 2025

              Oct 31        Nov 01        Nov 02
R1-R2            5%            5%           10%
R3 or greater    1%            1%            1%

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