156
FXXX10 KWNP 021231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Sep 02 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 6 (NOAA Scale
G2).
The greatest expected 3 hr Kp for Sep 02-Sep 04 2025 is 6.67 (NOAA Scale
G3).

NOAA Kp index breakdown Sep 02-Sep 04 2025

             Sep 02       Sep 03       Sep 04
00-03UT       5.33 (G1)    4.00         2.67
03-06UT       4.33         3.67         2.33
06-09UT       4.33         2.67         2.00
09-12UT       3.67         2.33         1.67
12-15UT       6.67 (G3)    2.00         1.67
15-18UT       5.00 (G1)    1.67         2.00
18-21UT       4.67 (G1)    1.67         2.00
21-00UT       3.67         2.33         2.33

Rationale: G1-G3 (Minor-Strong) geomagnetic storming periods are likely
on 02 Sep as CME effects persist.

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 Sep 02-Sep 04 2025

              Sep 02  Sep 03  Sep 04
S1 or greater   20%     10%     10%

Rationale: There is a slight chance for a greater than 10 MeV proton
event reaching the S1 (Minor) levels on 02-04 Sep with a large event
from AR 4197 being the most likely threat.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Sep 02-Sep 04 2025

              Sep 02        Sep 03        Sep 04
R1-R2           60%           60%           55%
R3 or greater   20%           20%           15%

Rationale: M-class flares (R1-R2/Minor-Moderate) are likely, with a
slight chance for an X-class flare (R3-Strong or greater), through 04
Sep primarily due to the flare potential exhibited from AR 4197.