:Product: 3-Day Forecast
:Issued: 2023 Sep 28 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 3 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 28-Sep 30 2023 is 3.67 (below NOAA
Scale levels).

NOAA Kp index breakdown Sep 28-Sep 30 2023

             Sep 28       Sep 29       Sep 30
00-03UT       1.67         1.67         2.67     
03-06UT       3.00         2.33         2.67     
06-09UT       0.67         2.00         2.33     
09-12UT       1.67         1.67         2.67     
12-15UT       1.33         2.33         3.67     
15-18UT       1.33         2.33         2.00     
18-21UT       1.67         2.67         2.67     
21-00UT       1.33         2.33         2.33     

Rationale: No G1 (Minor) or greater geomagnetic storms are expected.  No
significant transient or recurrent solar wind features are forecast.

B. NOAA Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-16 over the past 24 hours, was
below S-scale storm level thresholds.

Solar Radiation Storm Forecast for Sep 28-Sep 30 2023

              Sep 28  Sep 29  Sep 30
S1 or greater   10%      5%      5%

Rationale: There is a slight chance for S1 (Minor) solar radiation
storms on 28 Sep.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Sep 28 2023 0907 UTC.

Radio Blackout Forecast for Sep 28-Sep 30 2023

              Sep 28        Sep 29        Sep 30
R1-R2           35%           30%           30%
R3 or greater   10%            5%            5%

Rationale: There is a chance for isolated R1 (Minor) radio blackouts
through 30 Sep primarily due to ARs 3435 and 3445.