283
FXXX10 KWNP 101231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 10 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 3 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 10-Sep 12 2026 is 3.00 (below NOAA
Scale levels).

NOAA Kp index breakdown Sep 10-Sep 12 2026

             Sep 10       Sep 11       Sep 12
00-03UT       2.67         2.00         2.33
03-06UT       2.67         2.33         2.67
06-09UT       2.00         2.00         2.67
09-12UT       2.33         2.00         2.33
12-15UT       2.33         2.33         1.33
15-18UT       2.00         2.67         1.00
18-21UT       2.00         2.67         2.00
21-00UT       2.33         3.00         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-18 over the past 24 hours, was
below S-scale storm level thresholds.

Solar Radiation Storm Forecast for Sep 10-Sep 12 2026

              Sep 10  Sep 11  Sep 12
S1 or greater    1%      1%      1%

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 10-Sep 12 2026

              Sep 10        Sep 11        Sep 12
R1-R2           10%           10%            5%
R3 or greater    1%            1%            1%

Rationale: Solar activity is likely to be at very low to low levels with
a decreasing likelihood for C- and M-class flares (R1-R2/Minor-Moderate)
through 12 Sep as Region 4421 rotates beyond the West limb and other
regions on the visible disk continue to decay.