884
FXXX10 KWNP 130031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 13 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 13-Sep 15 2026 is 3.67 (below NOAA
Scale levels).

NOAA Kp index breakdown Sep 13-Sep 15 2026

             Sep 13       Sep 14       Sep 15
00-03UT       2.33         3.33         3.33
03-06UT       2.00         3.67         3.67
06-09UT       2.33         3.00         3.33
09-12UT       2.33         3.00         3.33
12-15UT       2.33         3.00         3.00
15-18UT       2.33         3.00         2.00
18-21UT       2.67         3.67         3.00
21-00UT       3.33         3.33         3.00

Rationale: No G1 (Minor) or greater geomagnetic storms are expected
through 15 Sep, though a solar sector boundary crossing and CH HSS are
anticipated to generate unsettled conditions on 13 Sep and isolated
active conditions on 14-15 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 13-Sep 15 2026

              Sep 13  Sep 14  Sep 15
S1 or greater    1%      1%      1%

Rationale: No S1 (Minor) or greater solar radiation storms are expected
through 15 Sep.

C. NOAA Radio Blackout Activity and Forecast

No radio blackouts were observed over the past 24 hours.

Radio Blackout Forecast for Sep 13-Sep 15 2026

              Sep 13        Sep 14        Sep 15
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 15 Sep.