184
FXXX10 KWNP 081231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 08 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 5 (NOAA Scale
G1).
The greatest expected 3 hr Kp for Sep 08-Sep 10 2026 is 5.00 (NOAA Scale
G1).

NOAA Kp index breakdown Sep 08-Sep 10 2026

             Sep 08       Sep 09       Sep 10
00-03UT       4.33         3.67         3.00
03-06UT       4.00         4.67 (G1)    2.67
06-09UT       5.00 (G1)    5.00 (G1)    2.33
09-12UT       3.67         3.67         2.00
12-15UT       4.67 (G1)    3.33         2.00
15-18UT       4.67 (G1)    3.33         0.67
18-21UT       4.33         3.00         1.33
21-00UT       3.33         2.67         1.33

Rationale: G1 (Minor) geomagnetic storms are likely through 09 Sep due
to combined positive polarity CH HSS effects and the anticipated arrival
of CMEs that left the Sun on 05 and 06 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 08-Sep 10 2026

              Sep 08  Sep 09  Sep 10
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 08-Sep 10 2026

              Sep 08        Sep 09        Sep 10
R1-R2           15%           15%           15%
R3 or greater    1%            1%            1%

Rationale: Solar activity is likely to be at low levels due to
occasional C-class flare activity, with a slight chance for M-class
flares (R1-R2/Minor-Moderate) through 10 Sep.