385
FXXX10 KWNP 060031
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Sep 06 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 06-Sep 08 2026 is 3.67 (below NOAA
Scale levels).

NOAA Kp index breakdown Sep 06-Sep 08 2026

             Sep 06       Sep 07       Sep 08
00-03UT       1.67         3.33         3.33
03-06UT       1.67         2.00         4.00
06-09UT       1.33         2.00         3.67
09-12UT       1.33         3.00         3.33
12-15UT       1.33         3.67         3.00
15-18UT       1.33         3.33         3.00
18-21UT       1.33         3.33         2.67
21-00UT       1.67         3.00         3.00

Rationale: While a CIR ahead of a positive polarity coronal high speed
stream and CME influences are anticipated to arrive on 07-08 Sep, no G1
(Minor) or greater geomagnetic storms are expected.

B. NOAA Solar Radiation Activity Observation and Forecast

Solar radiation, as observed by NOAA GOES-18 over the past 24 hours, was
above S-scale storm level thresholds.

Solar Radiation Storm Forecast for Sep 06-Sep 08 2026

              Sep 06  Sep 07  Sep 08
S1 or greater   75%     10%     10%

Rationale: S1 (Minor) solar radiation storms are expected on 06 Sep due
to elevated levels from eruptive activity on 05 Sep, decreasing to a
slight chance on 07-08 Sep, due to the source region remaining in a
geo-effective location.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Sep 05 2026 1518 UTC.

Radio Blackout Forecast for Sep 06-Sep 08 2026

              Sep 06        Sep 07        Sep 08
R1-R2           20%           20%           20%
R3 or greater    1%            1%            1%

Rationale: There is a slight chance for R1-R2 (Minor-Moderate) radio
blackouts through 08 Sep.