:Product: 3-Day Forecast
:Issued: 2026 Aug 29 0030 UTC
# Prepared by the U.S. Dept. of Commerce, NOAA, Space Weather Prediction Center
#
A. NOAA Geomagnetic Activity Observation and Forecast

The greatest observed 3 hr Kp over the past 24 hours was 4 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Aug 29-Aug 31 2026 is 5.67 (NOAA Scale
G2).

NOAA Kp index breakdown Aug 29-Aug 31 2026

             Aug 29       Aug 30       Aug 31
00-03UT       5.67 (G2)    2.67         1.67     
03-06UT       5.67 (G2)    3.67         2.00     
06-09UT       4.67 (G1)    3.67         1.67     
09-12UT       4.67 (G1)    2.67         1.67     
12-15UT       3.67         1.67         1.00     
15-18UT       3.67         1.00         1.00     
18-21UT       2.67         1.67         0.67     
21-00UT       2.67         2.67         2.00     

Rationale: Periods of G1-G2 (Minor-Moderate) geomagnetic storming are
likely on 29 Aug due to positive polarity CH HSS influences, coupled
with the anticipated arrival of CMEs that left the Sun on 25-26 Aug.

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 Aug 29-Aug 31 2026

              Aug 29  Aug 30  Aug 31
S1 or greater    5%      5%      5%

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 Aug 29-Aug 31 2026

              Aug 29        Aug 30        Aug 31
R1-R2           25%           25%           25%
R3 or greater    5%            5%            5%

Rationale: There is a chance for R1-R2 (Minor-Moderate) radio blackouts
on 28-30 Aug.