595
FXXX10 KWNP 110041
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 11 0040 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 11-Sep 13 2026 is 3.00 (below NOAA
Scale levels).

NOAA Kp index breakdown Sep 11-Sep 13 2026

             Sep 11       Sep 12       Sep 13
00-03UT       2.00         2.33         2.33
03-06UT       2.33         2.67         2.00
06-09UT       2.00         2.67         2.33
09-12UT       2.00         2.33         2.33
12-15UT       2.33         1.33         2.33
15-18UT       2.67         1.00         2.33
18-21UT       2.67         2.00         2.67
21-00UT       3.00         2.33         2.67

Rationale: No G1 (Minor) or greater geomagnetic storms are expected
through 13 Sep.

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 11-Sep 13 2026

              Sep 11  Sep 12  Sep 13
S1 or greater    1%      1%      1%

Rationale: No S1 (Minor) or greater solar radiation storms are expected
through 13 Sep.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Sep 11-Sep 13 2026

              Sep 11        Sep 12        Sep 13
R1-R2           10%           10%           10%
R3 or greater    1%            1%            1%

Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio
blackouts through 13 Sep.