012
FXXX10 KWNP 050031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Sep 05 0030 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 3 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 05-Sep 07 2025 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Sep 05-Sep 07 2025

             Sep 05       Sep 06       Sep 07
00-03UT       3.00         5.00 (G1)    3.67
03-06UT       2.33         4.67 (G1)    3.33
06-09UT       2.33         4.00         3.00
09-12UT       2.33         4.00         3.00
12-15UT       2.67         2.33         2.33
15-18UT       3.67         3.00         2.67
18-21UT       4.00         3.33         2.67
21-00UT       4.67 (G1)    3.33         3.00

Rationale: G1 (Minor) geomagnetic storm levels are likely on 05-06 Sep
due to recurrent CH HSS influences.

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 05-Sep 07 2025

              Sep 05  Sep 06  Sep 07
S1 or greater   10%     10%      5%

Rationale: There is a slight chance for a greater than 10 MeV proton
event reaching the S1 (Minor) levels through 06 Sep due to the flare
potential from AR 4197.

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 04 2025 1344 UTC.

Radio Blackout Forecast for Sep 05-Sep 07 2025

              Sep 05        Sep 06        Sep 07
R1-R2           55%           55%           40%
R3 or greater   10%           10%            5%

Rationale: Solar activity is expected to be low with a chance for
M-class flares (R1-R2, Minor-Moderate) and a slight chance for an
X-class flare (R3-Strong or greater), through 05 Sep primarily due to
the flare potential from AR 4197. Chances for M-class flares decrease on
07 Sep as AR 4197 rotates further around the W limb.