450
FXXX10 KWNP 061231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2025 Sep 06 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 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 06-Sep 08 2025 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Sep 06-Sep 08 2025

             Sep 06       Sep 07       Sep 08
00-03UT       4.00         3.67         3.00
03-06UT       3.67         3.33         2.67
06-09UT       4.00         5.00 (G1)    2.00
09-12UT       3.33         5.00 (G1)    2.67
12-15UT       3.33         4.00         2.67
15-18UT       3.00         3.00         2.00
18-21UT       2.33         3.00         2.67
21-00UT       5.00 (G1)    4.33         3.00

Rationale: G1 (Minor) geomagnetic storming is likely on 06 Sep due to
the aforementioned CH HSS effects. On 07 Sep, HSS activity combined with
the arrival of the 04 Sep CME is likely to cause further G1 (Minor)
storming levels with a chance for G2 (Moderate).

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 06-Sep 08 2025

              Sep 06  Sep 07  Sep 08
S1 or greater    5%      5%      5%

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 Sep 06-Sep 08 2025

              Sep 06        Sep 07        Sep 08
R1-R2           40%           35%           30%
R3 or greater    5%            5%            5%

Rationale: There is a chance for isolated R1-Minor radio blackouts
through 08 Sep due to the combined flare potential of Regions 4202 and
4207.