975
FXXX10 KWNP 011231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Sep 01 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 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 01-Sep 03 2025 is 6.67 (NOAA Scale
G3).

NOAA Kp index breakdown Sep 01-Sep 03 2025

             Sep 01       Sep 02       Sep 03
00-03UT       2.00         5.67 (G2)    3.67
03-06UT       1.33         5.67 (G2)    3.00
06-09UT       1.33         6.67 (G3)    2.67
09-12UT       1.33         5.67 (G2)    2.33
12-15UT       1.67         4.67 (G1)    2.00
15-18UT       1.67         4.67 (G1)    1.67
18-21UT       4.67 (G1)    4.00         1.33
21-00UT       5.67 (G2)    3.67         1.67

Rationale: Periods of G2 (Moderate) storming are likely, with a chance
for G3 (Strong) storm periods, late on 01 Sep due to the anticipated
arrival of the 30 Aug asymmetric full-halo CME. On 02 Sep, periods of G3
(Strong) storming are likely, with a chance for G4 (Severe) storm
periods, as CME effects persist. By 03 Sep, the solar wind environment
should decrease to quiet to active levels as CME influences diminish.

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 01-Sep 03 2025

              Sep 01  Sep 02  Sep 03
S1 or greater   75%     60%     25%

Rationale: The greater than 10 MeV proton flux is expected to reach S1
(Minor) storm levels on 01 Sep, especially following the initial arrival
of the 30 Aug CME. S1 conditions are likely to persist into 02 Sep, with
a chance for S1 levels on 03 Sep.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Sep 01-Sep 03 2025

              Sep 01        Sep 02        Sep 03
R1-R2           65%           65%           65%
R3 or greater   20%           20%           20%

Rationale: M-class flares (R1-R2/Minor-Moderate) are likely, with a
slight chance for an X-class flare (R3-Strong or greater), through 03
Sep.