184
FXXX10 KWNP 230031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 23 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 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 23-Sep 25 2026 is 5.33 (NOAA Scale
G1).

NOAA Kp index breakdown Sep 23-Sep 25 2026

             Sep 23       Sep 24       Sep 25
00-03UT       1.67         4.33         3.67
03-06UT       2.00         5.33 (G1)    3.67
06-09UT       2.00         4.67 (G1)    3.33
09-12UT       2.00         3.33         3.00
12-15UT       2.33         2.33         3.00
15-18UT       2.67         3.00         3.00
18-21UT       3.33         3.33         3.33
21-00UT       4.33         3.00         3.00

Rationale: G1 (Minor) geomagnetic storm conditions are likely on 24 Sep
due to CH HSS effects.

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 23-Sep 25 2026

              Sep 23  Sep 24  Sep 25
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 23-Sep 25 2026

              Sep 23        Sep 24        Sep 25
R1-R2           20%           20%           20%
R3 or greater    1%            1%            1%

Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio
blackouts on 23-25 Sep.