539
FXXX10 KWNP 221231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 22 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 2 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Sep 22-Sep 24 2026 is 5.33 (NOAA Scale
G1).

NOAA Kp index breakdown Sep 22-Sep 24 2026

             Sep 22       Sep 23       Sep 24
00-03UT       2.00         1.67         4.33
03-06UT       0.67         2.00         5.33 (G1)
06-09UT       0.33         2.00         4.67 (G1)
09-12UT       0.33         2.00         3.33
12-15UT       2.00         2.33         2.33
15-18UT       0.67         2.67         3.00
18-21UT       1.67         3.33         3.33
21-00UT       1.67         4.33         3.00

Rationale: G1 (Minor) geomagnetic storm conditions are likely 24 Sep
under +CH HSS influences

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 22-Sep 24 2026

              Sep 22  Sep 23  Sep 24
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 22-Sep 24 2026

              Sep 22        Sep 23        Sep 24
R1-R2           15%           15%           15%
R3 or greater    1%            1%            1%

Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio
blackouts through 24 Sep primarily due to the flare potential of Regions
4534 and 4536.