:Product: 3-Day Forecast
:Issued: 2026 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 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Oct 31-Nov 02 2026 is 4.67 (NOAA Scale
G1).

NOAA Kp index breakdown Oct 31-Nov 02 2026

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

Rationale: Periods of G1 (Minor) geomagnetic storming are likely on 31
Oct-01 Nov due to the influence of a positive polarity CH HSS.

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 2026

              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 2026

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

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