096
FXXX10 KWNP 261231
DAYTDF

:Product: 3-Day Forecast
:Issued: 2026 Aug 26 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 1 (below NOAA
Scale levels).
The greatest expected 3 hr Kp for Aug 26-Aug 28 2026 is 5.67 (NOAA Scale
G2).

NOAA Kp index breakdown Aug 26-Aug 28 2026

             Aug 26       Aug 27       Aug 28
00-03UT       0.33         3.67         5.67 (G2)
03-06UT       0.67         3.33         4.67 (G1)
06-09UT       0.67         3.33         4.00
09-12UT       1.00         3.00         4.00
12-15UT       0.33         3.67         3.67
15-18UT       0.67         3.67         4.00
18-21UT       1.00         3.67         4.00
21-00UT       1.67         4.67 (G1)    4.67 (G1)

Rationale: G1 (Minor) geomagnetic storms are likely by late on 27 Aug
due to positive polarity CH HSS effects. G1-G2 (Minor-Moderate)
geomagnetic storms are likely on 28 Aug under combined effects from
positive polarity CH HSS effects and CME influences from events that
left the Sun on 25 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 26-Aug 28 2026

              Aug 26  Aug 27  Aug 28
S1 or greater   10%     10%     10%

Rationale: A slight chance for S1 (Minor) radiation storms will persist
through 28 Aug primarily driven by the current flare potential of Region
4513.

C. NOAA Radio Blackout Activity and Forecast

Radio blackouts reaching the R1 levels were observed over the past 24
hours. The largest was at Aug 26 2026 0634 UTC.

Radio Blackout Forecast for Aug 26-Aug 28 2026

              Aug 26        Aug 27        Aug 28
R1-R2           55%           55%           55%
R3 or greater   15%           15%           15%

Rationale: R1-R2 (Minor-Moderate) radio blackouts are likely, with a
slight chance for an isolated R3 (Strong) event, through 28 Aug
primarily driven by the current flare potential of Region 4513.